On another thread I went over my woes (and ultimate failure) surrounding my attempt to get factory Sirius installed on my E60. It's an '04 530i, and I apparently missed the mark when the sat prep was standard by only a few months. That took an ordinarily $500 retrofit and turned it into a $10,000+ overhaul which is obviously not an option at all.
So that got me thinking: the shark fin antenna on my car. I did some research with BMW and they state that there's only one type of antenna they put on the E60. That antenna is capable of receiving satellite, even if the sat prep isn't installed. My suspicion was that if Alpine makes the electronics on the car, it's possible that they used the standard satellite radio connector which means that I might be able to use the factory antenna with an aftermarket system. The technician I spoke with at BMW suggested that it might be possible but he wasn't sure. They unfortunately didn't have a loose antenna in their parts department that I could take a look at.
I'm not sure exactly where to look to track down the wires coming from the antenna. I would imagine that if it has the satellite capability built in, that the satellite signal wire runs separate. Where exactly does the antenna wiring terminate? If I remember correctly it comes in somewhere on the left side of the trunk but before I tear the trunk apart it'd be helpful to have a better idea of what I'm looking for.

Anyone familiar with the antenna wiring or can someone point me to any diagrams that could help me track everything down?
This is kind of my plan B, because I really don't want to put that fugly aftermarket antenna on my car! Any help would be appreciated.
