How to wire a trailer electric brake controller?

[ChipB]

I'm planning on installing the BMW Class III hitch and wire harness on my new F15, but I'm trying to figure out how to wire in a electric brake controller. I know the E70's did not have a pre-wired connector for a controller - does anyone know whether they added that for the F15, because it would certainly make this project a bit easier. I've seen some articles on wiring a controller for the E70 which involves making a splice into a light control module behind the glove box - this is to get a 12 volt source for brake light status. If the F15 does not have a pre-wired connector for a brake controller then I suppose the process would have to be similar, but is it identical? Any advice on how to do this would be appreciated.