You can use metro or any other WS stack as part of your deployment.
Just make sure you disable webservices subsystem and bundle whole metro as part of your deployment.
I have a similar question: I have Wildfly 8 and I should be able to use JAX-WS RI reather than Apache CXF (I do need only WebService client; I have no WebService endpoints to serve). I deactivated the webservices subsystem in my standalone.xml but still apache cxf is used as JAX-WS client. What can I do?
You may probably also have a look at my full problem: http://stackoverflow.com/questions/37158821/wildfly-how-to-use-jaxws-ri-instead-of-apache-cxf-webservice-client-only