Right.....just come back from my local BMW dealer.
Tried a "proper" MP3 CD on an E90 without Navi and it worked perfectly. I was able to List all the MP3's stored on the disc etc.....
Tried it on a Navi-Pro system (with 6 CD changer) and nothing. Didnt recognise the disc when it was in the slot loader or the changer.
Asked them about iPodYourBMW (
www.ipodyourbmw.com) for UK E90's and they havent even heard of it.......
Looks like we either have you wait for a s/w update for Navi-pro or wait for an aftermarket solution.