I checked it with jboss 4.2.3.GA. And have the same situation:
Service port is created successfully, but method invocation fault with NPE exception or ClassCastException.
I plan to play with classpaths. maybe we have conflict between application and jboss library...
Have anybody ideas?
I resolved the problem.
The problem was with extra jboss libraries inside my jar, like jbossws, ...
When I removed them all works fine.
I have same problem as you had.....can you please tell me whick jar files you remove and from where?
Thanks in advance