I'm about to get a bluetooth headset, and I was wondering: If I'm using the 3.5mm jack to the car aux in for music/navigation and I get a call with the bluetooth in, what will happen? Will I continue to get the music and or navigation prompts going to the car stereo while I talk? What about if I'm just using the navigation, or navigation through the phone's speaker with the jack unplugged? I'd like to be able to take a call via bluetooth and not lose nav prompts. Thanks!