Hi Darran, here is what i came up with. We got two problems: a) Type substitution at runtime b) Tooling support for inheritance The first one is supported since we introduced JAXB 2.1. Please see the following JIRA as refernce. http://jira.jboss.org/jira/browse/JBWS-1591 It's basically there since 2.0. The tooling is not available and will come with JAX-WS 2.1, which we currently don't support. However the tests have shown that manually adding the @XmlSeeAlso annotation to your samples does work as expected. Please see the following references for further explanations: https://jax-ws.dev.java.net/roadmap/jaxws21-plan.html http://weblogs.java.net/blog/kohlert/archive/community_java_web_services_... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4138128#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...