It is unreasonable to expect that a ws4ee client can download metadata that relate to its own java nature from the endpoint it is talking to.
WS is about interoperability and client/server side are fundamentally disconnected. Your client might be talking to a .NET endpoint, which will have no notion of xml/java mapping.
The route to take is, to use a tool like wscompile to generate all the required ws4ee artifacts (including jaxrpc-mapping.xml) from the abstract contract (the wsdl) and package them with your client in a standard way. A portable client cannot get coupled to the java nature of the endpoint. The endpoint is free to change its implementation any time.
In short: generate jaxrpc-mapping.xml from wsdl, don't expect the endpoint to provide it
Thanks for the answer! It's clear that it depends on the client which "mapping" to use, I was hoping that there was an easier way for a java client to use the jaxrpc-mapping of the ("java") server. But reading the wsdl, use wscompile to generate the mapping on client side again isn't too much work ;-)
Maybe your friend can email it to you, together with the service endpoint interface (SEI) and all associated complex types that form the transitive type closure.