I just bought a new car (new to me anyway, a smart cabrio). And it has an auxilary plug in the glovebox. Well using the htc all-in-one adapter I hooked up my g1 to the car to try to play music through the stereo. Well it wouldn't work, it would only play through the speakerphone. I finally found a post talking about how the htc adapter and some other adapter won't work with thecupcake update and a link was given for an app that allowed me to switch manually between speakerphone and headphone. I now can play the music on my G1 through my car speakers. I thought in theory I should be able to make and receive phone calls as well through the car speakers. Well theory doesn't alway translate to real world... I can hear whomever I'm speaking to through the stereo speakers just fine but they cannot hear me, even if I'm speaking directly into the G1 mic. My guess is that when it is manually forced to send all audio through headphone it also only receives mic input through headphones as well. So.... does anyone know of anyway to make this work to where not only do I hear the person I'm speaking to through my car speakers but they can also hear me somehow?