Is there a way to handle SOAP requests asynchronously in a JAX-WS web service?

Issue

• Does JBoss provide any supported way to handle SOAP requests in an asynchronous manner (long poll) without callbacks?
• I would like to pause the processing of a message and resume it when an external system is ready. But I would not want to lock up the request thread but rather send the response back from some other thread when the processing is done.
• I have external clients calling using HTTP (most likely SOAP) and this request could take 1-2 seconds to complete so I would prefer not to lock the incoming thread but rather use NIO and return a response when it is ready (from some other thread).
• JAX-RS 2.0 has this type of syntax, i.e. @Suspended that returns the response from some other thread and releasing the request thread. But I am probably stuck with SOAP and the server is not JavaEE 7 compatible in any case.
• It should also be possible to do this a raw servlet and startAsync(), but then I would have to invent the SOAP part.