Thanks man! I have USB cables carefully wired in my car now from my S3, and wanted to know if I could use the same setup. Your post gives me hope :D
Don't thank me before you try it. The interface for me in my car (late model Mercedes) was unusably slow. I've done enough here to prove that the phone is recognised by the car and audio flows out through the usb lead. I'd never use this method to listen to music
Your mileage may vary with other manufacturers though.
I have a Lumia 920, it worked for the first time when it connected to my 2013 BMW, it showed up as Lumia 920 and the music is coming out from Car audio system with USB. Strange enough, right after that, I was never able to make it work again. The device (phone) will still show up and recognized as Lumia 920, and the phone will still be charged, then no songs can be seen in the car system. Not sure if I changed anything in Nokia Music?