The StatelessContainer's method invokeEndpoint(Method method, Object[] args, InvocationContextCallback invCtxCallback) currently get the WebServiceContext instance using the right jbossws-spi factory. This is an issue with the JBossWS-Metro stack as we should use the WebServiceContext it already provides.
This should be passed in as an attachment in the InvocationContextCallback.

Something like this should work:

...
WebServiceContext providedCtx = invCtxCallback.getAttachment(WebServiceContext.class);
if (providedCtx != null)
{
//use the provided one through a delegate
jaxwsContext = new WebServiceContextDelegate(providedCtx);
}
else
{
//do as we used to do
jaxwsContext = contextFactory.newWebServiceContext(InvocationType.JAXWS_EJB3, invCtxCallback.get(javax.xml.ws.handler.MessageContext.class));
}
...

This requires jbossws-spi 1.0.7 to be released and specified in the dependencies because of the WebServiceContextDelegate.