We currently have no special integration with the container for jaxws handlers created from a predefined client/endpoint configuration. We need to support @PostConstruct, @PreDestroy methods, as well as @EJB, @Resource and CDI injection.
Most likely this basically boils down to having AS components created for these handlers too, the same we have for jaxws handlers created after having parsed the @HandlerChain annotation. See org.jboss.as.webservices.deployers.WSIntegrationProcessorJAXWS_HANDLER and org.jboss.as.webservices.injection.WSHandlerChainAnnotationProcessor as starting point.