Our version of JAXWS api uses the original mechanisms for detecting the javax.xml.ws.spi.Provider class to use and create a new instance of.
On AS7 we need to hide our implementations from the client runtime classpath; as a result of that we can't "pollute" the thread context classloader with the jbossws / cxf / etc. impl jars, so the JAXWS api Provider impl detection (that is based upon service loader) won't work properly.
Moreover, there's likely to be a requirement for supporting the option of users overriding the JAXWS provider impl to use in a given deployment.

So, our jaxws api should be able (at least) to dynamically load the jbossws jaxws client implementation module (without affecting the TCCL) and use that for resolving the javax.xml.ws.spi.Provider to use.