The jbossws-native-jaxrpc.jar is currently installed in the endorsed dir lib along with the jaxws and saaj native jars. That's not strictly required (the reason for having the other libs there is to make sure jaxws native impl is loaded before the jdk ones when using jdk 1.6) and causes failures in the signaure module of JavaEE 5 TCK as the jaxrpc API refers to the Servlet API which of course is not in the endorsed dir.