I have the same problem. 2005 BMW X5 that I can't pair the Blackjack to. That being said, if I hold the 'talk' button on the steering wheel I don't get the beep I was accustomed to in my e46 3 series.

I haven't tried another phone, but the Blackjack pairs great in my 2006 Z4 M Roadster. I wonder if the ULFs are different or not... any thoughts?