I have an HTC Desire, just upgraded to 2.2 (seems a bit slower) and I would like to have the navigation instructions routed through bluetooth to come through the car stereo speakers. Now I know this can be done with A2DP but I was wondering if it can be made to work over HFP? Over A2DP it works but it means you cannot listen to any of the in-car sourses like CD or radio as you have to have it permanently switched to bluetooth audio to hear the instructions. If it was over HFP, the car stereo would mute whatever source you were listening to so it could play the navigation instruction. Is there a way to make this work, or an app to download?