Hmm weird
I think space warps can work on a sub object level but not nessicerly affect the modifiers or gizmos ( or probably doing something that whoever wrote the ffd sapcw warp didn't think someone would do with it ).
i would try linking your uvw map gizmo to a dummy then attatch that dummy to a vertex using the linked x-form modifier.....that way your uvw map will be attached to that vertex ( sub-object level ) and not the object.