exactly but the servlet element should stay in the sipservlet namespace as per the sipapp xsd. This is why I said I needed to duplicate the existing metadata classes (everytime the sipapp xsd import a javaee type such as servletType or listenerType) and only apply the JBossXmlNsPrefix to the attributes of those duplicated classes. I did that and it works like a charm. Thanks for your help ! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4201419#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...