Brian-bmw, rastaFarai
Thank you for the comments. Like I said I got the TCU from a friends X5. In his car, there was a purple and a white. In mine there were two purples. And these two are physically keyed. One purple connector would fit to the purple coded jack, I just had to cut a small notch in it. I think this is the antenna wire which comes to the center console, where you care suppose to connect the bluetooth antenna.

In short, I manged to get it to work.....sort of. It paired just fine. But the signal is very weak, I couldn't find the bluetooth antenna on my friends 2005 X5 3.0i. Does anyone know where it is located in the vechicle?

I think if I hook the anteena to the wire that comes to the center console everything should work just fine. It didn't recoginise the voice command though. When I press the "speak button on steering wheel", it asks me what I want to do, but it doesn't quite do anything. I guess I need to play around with it.