I was able to take part in the promotion to get a GPS with the purchase of my R1200RT and it was installed last weekend by the dealer at no cost. The problem I have is it I can't figure out how to make it play through the speakers. When I try to adjust the volume on the device itself it says something to the effect that it's hooked up through the audio system but I never hear anything. I've tried it on AUX, USB, FM, Satellite etc but no sound ever comes out. I've flipped through the audio system manual and the one for the GPS and I can't find where it says how it should all work. I'm sure it's something simple but I can't figure it out.