you need the Ibus interface http://www.reslers.de/IBUS/index.html

plus you need a few ibus monitoring programs, i was doing this same project for my 2002 x5 but had to put it on hold for now.

if you need more info try the links below and if you can`t find the programs PM me

http://www.mp3car.com/

http://www.carcpu.com/

http://febsperanza.3plast.com/

http://www.cartft.com/

http://www.logicsupply.com/default.php