Annotations inherited by a resource class should determine parameter type from the subclass, not the superclass

I have a generic service interface, like so:

public interface GenericService<T> {
@POST
@Consumes(MediaType.APPLICATION_JSON)
public void doSomething(T obj);
}

And an implementation of the interface, like so:

@Path("/impl")
public class Impl implements GenericService<RealJAXBType> {
public void doSomething(RealJAXBType obj)

{ // blah blah }

}

RealJAXBType is annotated as a JAXB XMLRootElement. For information's
sake, I'm using Apache Wink 1.1 with Jackson 1.5.5.

When I call the service exposed by the Wink servlet, Wink attempts to
deserialize the passed JSON content to an HashMap of some description, not
a RealJAXBType. I assume that's because the @POST annotation is on the
generic interface. My guess is that Wink picks up the "class" of T, which
is of course Object (as generic type T isn't scoped), and based on this,
attempts a best-effort conversion into a HashMap, which is incompatible
with the implementation's type of RealJAXBType.

I've verified this happens for an abstract superclass as well as an
interface, so I guess it's to do with the annotation inheritance code.

This seems unintuitive - I'd certainly expect Wink to look at the
implementation parameter's class when deciding what to attempt to
deserialise the JSON content into. Ideally, I'd like Wink to heed the
type of the implementation.