StandardSession#getLastAccessedTime() uses wrong message key. This class uses "standardSession.getId.ise", but it should be "standardSession.getLastAccessedTime.ise". DeltaSession do ditto. This bug is in tc5.5.x and tc6.0.x.
Created attachment 18181 [details] patch for /tomcat/container/tc5.5.x
Created attachment 18182 [details] patch for /tomcat/tc6.0.x/trunk
Hups, many thanks to reporting this. Is fixed at next release. Peter