Index: Core/LoggingEvent.cs
===================================================================
--- Core/LoggingEvent.cs	(revision 330682)
+++ Core/LoggingEvent.cs	(working copy)
@@ -827,7 +827,7 @@
 				{
 #if (NETCF || SSCLI)
 					// On compact framework there's no notion of current Windows user
-					m_data.UserName = "NOT AVAILABLE";
+					m_data.UserName = SystemInfo.NotAvailableText;
 #else
 					try
 					{
@@ -875,7 +875,7 @@
 				{
 #if (NETCF || SSCLI)
 					// On compact framework there's no notion of current thread principals
-					m_data.Identity = "NOT AVAILABLE";
+					m_data.Identity = SystemInfo.NotAvailableText;
 #else
 					try
 					{
Index: ObjectRenderer/DefaultRenderer.cs
===================================================================
--- ObjectRenderer/DefaultRenderer.cs	(revision 330682)
+++ ObjectRenderer/DefaultRenderer.cs	(working copy)
@@ -17,7 +17,6 @@
 #endregion
 
 using System;
-using System.Text;
 using System.IO;
 using System.Collections;
 
@@ -40,8 +39,6 @@
 	/// <author>Gert Driesen</author>
 	public sealed class DefaultRenderer : IObjectRenderer
 	{
-		private static readonly string NewLine = SystemInfo.NewLine;
-
 		#region Constructors
 
 		/// <summary>
@@ -144,7 +141,7 @@
 
 			if (obj == null)
 			{
-				writer.Write("(null)");
+				writer.Write(SystemInfo.NullText);
 				return;
 			}
 			
@@ -169,7 +166,7 @@
 			}
 
 			string str = obj.ToString();
-			writer.Write( (str==null) ? "(null)" : str );
+			writer.Write( (str==null) ? SystemInfo.NullText : str );
 		}
 
 		#endregion
Index: ObjectRenderer/RendererMap.cs
===================================================================
--- ObjectRenderer/RendererMap.cs	(revision 330682)
+++ ObjectRenderer/RendererMap.cs	(working copy)
@@ -18,6 +18,7 @@
 
 using System;
 using System.IO;
+using log4net.Util;
 
 namespace log4net.ObjectRenderer
 {
@@ -109,7 +110,7 @@
 		{
 			if (obj == null)
 			{
-				writer.Write("(null)");
+				writer.Write(SystemInfo.NullText);
 			}
 			else 
 			{
Index: Repository/Hierarchy/XmlHierarchyConfigurator.cs
===================================================================
--- Repository/Hierarchy/XmlHierarchyConfigurator.cs	(revision 330682)
+++ Repository/Hierarchy/XmlHierarchyConfigurator.cs	(working copy)
@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections;
+using System.Configuration;
 using System.Globalization;
 using System.Reflection;
 using System.Xml;
@@ -99,7 +100,7 @@
 				string debugAttribute = element.GetAttribute(INTERNAL_DEBUG_ATTR);
 				LogLog.Debug("XmlHierarchyConfigurator: "+INTERNAL_DEBUG_ATTR+" attribute [" + debugAttribute + "].");
 
-				if (debugAttribute.Length>0 && debugAttribute != "null") 
+				if (debugAttribute.Length > 0 && debugAttribute != "null") 
 				{	  
 					LogLog.InternalDebugging = OptionConverter.ToBoolean(debugAttribute, true);
 				}
@@ -109,7 +110,7 @@
 				}
 
 				string confDebug = element.GetAttribute(CONFIG_DEBUG_ATTR);
-				if (confDebug.Length>0 && confDebug != "null")
+				if (confDebug.Length > 0 && confDebug != "null")
 				{	  
 					LogLog.Warn("XmlHierarchyConfigurator: The \"" + CONFIG_DEBUG_ATTR + "\" attribute is deprecated.");
 					LogLog.Warn("XmlHierarchyConfigurator: Use the \"" + INTERNAL_DEBUG_ATTR + "\" attribute instead.");
@@ -117,6 +118,26 @@
 				}
 			}
 
+#if !NETCF
+			// Look for log4net.NullText in AppSettings
+			string nullTextAppSettingsKey = ConfigurationSettings.AppSettings["log4net.NullText"];
+			if (nullTextAppSettingsKey != null && nullTextAppSettingsKey.Length > 0)
+			{
+				LogLog.Debug("XmlHierarchyConfigurator: Replacing default SystemInfo.NullText value [" + SystemInfo.NullText + "] with [" + nullTextAppSettingsKey + "].");
+				SystemInfo.NullText = nullTextAppSettingsKey;
+			}
+#endif
+
+#if !NETCF
+			// Look for log4net.NotAvailableText in AppSettings
+			string notAvailableTextAppSettingsKey = ConfigurationSettings.AppSettings["log4net.NotAvailableText"];
+			if (notAvailableTextAppSettingsKey != null && notAvailableTextAppSettingsKey.Length > 0)
+			{
+				LogLog.Debug("XmlHierarchyConfigurator: Replacing default SystemInfo.NotAvailableText value [" + SystemInfo.NotAvailableText + "] with [" + notAvailableTextAppSettingsKey + "].");
+				SystemInfo.NotAvailableText = notAvailableTextAppSettingsKey;
+			}
+#endif
+
 			// Default mode is merge
 			ConfigUpdateMode configUpdateMode = ConfigUpdateMode.Merge;
 
@@ -1033,6 +1054,8 @@
 		private const string ADDITIVITY_ATTR			= "additivity";  
 		private const string THRESHOLD_ATTR				= "threshold";
 		private const string CONFIG_DEBUG_ATTR			= "configDebug";
+		private const string NULL_TEXT_ATTR				= "nullText";
+		private const string NOT_AVAILABLE_TEXT_ATTR	= "notAvailableText";
 		private const string INTERNAL_DEBUG_ATTR		= "debug";
 		private const string CONFIG_UPDATE_MODE_ATTR	= "update";
 		private const string RENDERING_TYPE_ATTR		= "renderingClass";
@@ -1057,4 +1080,4 @@
 
 		#endregion Private Instance Fields
 	}
-}
+}
\ No newline at end of file
Index: Util/PatternConverter.cs
===================================================================
--- Util/PatternConverter.cs	(revision 330682)
+++ Util/PatternConverter.cs	(working copy)
@@ -16,12 +16,10 @@
 //
 #endregion
 
-using System;
 using System.Text;
 using System.IO;
 using System.Collections;
 
-using log4net.Core;
 using log4net.Util;
 using log4net.Repository;
 
@@ -339,7 +337,7 @@
 				// Don't have a repository to render with so just have to rely on ToString
 				if (value == null)
 				{
-					writer.Write( "(null)" );
+					writer.Write( SystemInfo.NullText );
 				}
 				else
 				{
Index: Util/PatternStringConverters/IdentityPatternConverter.cs
===================================================================
--- Util/PatternStringConverters/IdentityPatternConverter.cs	(revision 330682)
+++ Util/PatternStringConverters/IdentityPatternConverter.cs	(working copy)
@@ -16,8 +16,6 @@
 //
 #endregion
 
-using System;
-using System.Text;
 using System.IO;
 
 using log4net.Util;
@@ -49,7 +47,7 @@
 		{
 #if (NETCF || SSCLI)
 			// On compact framework there's no notion of current thread principals
-			writer.Write( "NOT AVAILABLE" );
+			writer.Write( SystemInfo.NotAvailableText );
 #else
 			try
 			{
@@ -66,7 +64,7 @@
 				// some undefined set of SecurityPermission flags.
 				LogLog.Debug("IdentityPatternConverter: Security exception while trying to get current thread principal. Error Ignored.");
 
-				writer.Write( "NOT AVAILABLE" );
+				writer.Write( SystemInfo.NotAvailableText );
 			}
 #endif
 		}
Index: Util/PatternStringConverters/ProcessIdPatternConverter.cs
===================================================================
--- Util/PatternStringConverters/ProcessIdPatternConverter.cs	(revision 330682)
+++ Util/PatternStringConverters/ProcessIdPatternConverter.cs	(working copy)
@@ -16,8 +16,6 @@
 //
 #endregion
 
-using System;
-using System.Text;
 using System.IO;
 
 using log4net.Util;
@@ -49,7 +47,7 @@
 		{
 #if (NETCF || SSCLI)
 			// On compact framework there is no System.Diagnostics.Process class
-			writer.Write( "NOT AVAILABLE" );
+			writer.Write( SystemInfo.NotAvailableText );
 #else
 			try
 			{
@@ -61,7 +59,7 @@
 				// some undefined set of SecurityPermission flags.
 				LogLog.Debug("ProcessIdPatternConverter: Security exception while trying to get current process id. Error Ignored.");
 
-				writer.Write( "NOT AVAILABLE" );
+				writer.Write( SystemInfo.NotAvailableText );
 			}
 #endif
 		}
Index: Util/PatternStringConverters/UserNamePatternConverter.cs
===================================================================
--- Util/PatternStringConverters/UserNamePatternConverter.cs	(revision 330682)
+++ Util/PatternStringConverters/UserNamePatternConverter.cs	(working copy)
@@ -16,8 +16,6 @@
 //
 #endregion
 
-using System;
-using System.Text;
 using System.IO;
 
 using log4net.Util;
@@ -49,7 +47,7 @@
 		{
 #if (NETCF || SSCLI)
 			// On compact framework there's no notion of current Windows user
-			writer.Write( "NOT AVAILABLE" );
+			writer.Write( SystemInfo.NotAvailableText );
 #else
 			try
 			{
@@ -66,7 +64,7 @@
 				// some undefined set of SecurityPermission flags.
 				LogLog.Debug("UserNamePatternConverter: Security exception while trying to get current windows identity. Error Ignored.");
 
-				writer.Write( "NOT AVAILABLE" );
+				writer.Write( SystemInfo.NotAvailableText );
 			}
 #endif
 		}
Index: Util/SystemInfo.cs
===================================================================
--- Util/SystemInfo.cs	(revision 330682)
+++ Util/SystemInfo.cs	(working copy)
@@ -53,6 +53,24 @@
 
 		#endregion Private Instance Constructors
 
+		#region Public Static Constructor
+
+		/// <summary>
+		/// Initialize default values for private static fields.
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// Only static methods are exposed from this type.
+		/// </para>
+		/// </remarks>
+		static SystemInfo()
+		{
+			s_notAvailableText = "NOT AVAILABLE";
+			s_nullText = "(null)";
+		}
+
+		#endregion
+
 		#region Public Static Properties
 
 		/// <summary>
@@ -239,7 +257,7 @@
 					// Couldn't find a value
 					if (s_hostName == null || s_hostName.Length == 0)
 					{
-						s_hostName = "NOT AVAILABLE";
+						s_hostName = s_notAvailableText;
 					}
 				}
 				return s_hostName;
@@ -295,15 +313,13 @@
 
 					if (s_appFriendlyName == null || s_appFriendlyName.Length == 0)
 					{
-						s_appFriendlyName = "NOT AVAILABLE";
+						s_appFriendlyName = s_notAvailableText;
 					}
 				}
 				return s_appFriendlyName;
 			}
 		}
 
-		private static DateTime s_processStartTime = DateTime.Now;
-
 		/// <summary>
 		/// Get the start time for the current process.
 		/// </summary>
@@ -329,6 +345,35 @@
 			get { return s_processStartTime; }
 		}
 
+		/// <summary>
+		/// Text to output when a <c>null</c> is encountered.
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// Use this value to indicate a <c>null</c> has been encountered while
+		/// outputing a string representation of an item.
+		/// </para>
+		/// </remarks>
+		public static string NullText
+		{
+			get { return s_nullText; }
+			set { s_nullText = value; }
+		}
+
+		/// <summary>
+		/// Text to output when an unsupported feature is requested.
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// Use this value when an unsupported feature is requested.
+		/// </para>
+		/// </remarks>
+		public static string NotAvailableText
+		{
+			get { return s_notAvailableText; }
+			set { s_notAvailableText = value; }
+		}
+
 		#endregion Public Static Properties
 
 		#region Public Static Methods
@@ -858,6 +903,21 @@
 		/// </summary>
 		private static string s_appFriendlyName;
 
+		/// <summary>
+		/// Text to output when a <c>null</c> is encountered.
+		/// </summary>
+		private static string s_nullText;
+
+		/// <summary>
+		/// Text to output when an unsupported feature is requested.
+		/// </summary>
+		private static string s_notAvailableText;
+
+		/// <summary>
+		/// Start time for the current process.
+		/// </summary>
+		private static DateTime s_processStartTime = DateTime.Now;
+
 		#endregion
 
 		#region Compact Framework Helper Classes
Index: Util/ThreadContextStacks.cs
===================================================================
--- Util/ThreadContextStacks.cs	(revision 330682)
+++ Util/ThreadContextStacks.cs	(working copy)
@@ -16,9 +16,6 @@
 //
 #endregion
 
-using System;
-using System.Collections;
-
 namespace log4net.Util
 {
 	/// <summary>
@@ -84,7 +81,7 @@
 					if (stack == null)
 					{
 						// Property is not set to a stack!
-						string propertyValueString = "(null)";
+						string propertyValueString = SystemInfo.NullText;
 
 						try
 						{