OldParallelGC is an old implementation and the New implementation (from 1.4.1) should be better most times for JBoss and such long running servers. So drop -XX:UseParallelOldGC, also I would drop -XX:+CMS stuff.
Also fixing the eden space (NewSize) might have bad sideeffects because of reducing the OldGen.
I recommed to use the latest 1.5. JVM!