The Java property "os.name" is "Windows Server 2008 R2" on R2 system.
"osname=win32" in the Bundle-NativeCode entry doe not work, this exception is thrown:org.osgi.framework.BundleException: Unresolved constraint in bundle native-lib-windows-x86 : No matching native libraries found.
This osname alias needs to be added to the felix framework.
There is a workaround, just add
osname="windows server 2008 r2";
in the Bundle-NativeCode entry.