Just bought the Palm car kit. I have the stereo adapter to use with earphones, but when I plug it into the output on the back of the GPS unit to try to use it with my car (Prius) aux plug, nothing happens. It does work from the GPS to earphones, so is this a Prius issue, or do I need to NOT use the Treo stereo adapter, and use a cable going straight from the GPS output to the Prius Aux input?