The XML Schema allows for deriving types from other types. Java-XML binding frameworks such as JAXB match type derivation with class inheritance. Therefore, the Command service should not be hard to expose. Regarding invocation, be careful, don't treat web services as RMI. For a document-oriented service, the notion of "parameters" has no meaning. We must devise a way to assemble an XML document from the process variables. I remember discussing this topic some time ago (in the sourceforge forums!). Back then I rounded up the conclusions and put together a paper. I just attached it to a Wiki page. We can pick up from there. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3957176#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...