As far as I can remember (JBoss 4.0.4 came a lot of time before I started being involved in JBossWS), there was a partial/initial implementation of JAXWS available at that time. So it's might even be the @WebServiceProvider was not implemented. The reccomended solution here is to move to a recent JBoss/JBossWS version as soon as possible, not only for this reason.