I have a slight modification to the location of the Prodigy so that I can remove it when I'm not towing. You can see it here. It may help someone.
2004 BMW X5 Hitch
It sounds like we all have to run the brake wire to the rear, right? Doesn't it seem like there should be a provision for this in the factory wiring, or does BMW feel that too few people will pull trailers with brakes?