do you find a solution ?
I have the same error, similar ...
11-jun-2010 10:50:20 com.sun.enterprise.transaction.JavaEETransactionManagerSimplified initDelegates
INFO: Using com.sun.enterprise.transaction.jts.JavaEETransactionManagerJTSDelegate as the delegate
java.lang.ClassCastException: $Proxy49 cannot be cast to org.jboss.ws.core.StubExt
I have to sing de the soap message
I ' am follow the free chapter 9 of jboss in action, and not mention modifications in the Client class if you need ws-security.
thanks!