I found a reference to using the MessageContext to retrieve this information:
Code:

MessageContext messageContext = this.ctx.getMessageContext();
HttpServletRequest request = (HttpServletRequest) messageContext.getProperty("transport.http.servletRequest");

but I looked at my message context at runtime and it wasn't holding any property. The ServletEndpointContextImpl (the JBWS object implementing ServletEndpointContext) does contain references to the HttpServletRequest and HttpServletResponse.

What is the J2EE-compliant way to retrieve this information?