No USB Audio in my BMW after 3.0 upgrade iPhone 3G

I upgraded my iPhone to 3.0 and now it is not recognized as an external audio device by the iDrive in my BMW any more. Prior to the upgrade, as soon as the phone was clicked into the cradle in the car, the play-lists were available on the screen. Please, Apple, come out with a patch to make the USB audio work again. Or let me know how to downgrade from 3.0 - as being able to play music is more important to me than cut and paste! Thanks.
iPhone 3G iPhone OS 3.0 BMW Z4 with smartphone USB audio interface