It is my understanding that the Treo 600 headphone jack is 2.5mm (the standard size for headsets). I think that HS should make a wired remote accessory. The end that plugs in to the Treo would be a 2.5mm jack, and the other end would be the remote with a 3.5mm jack for headphones. This would also help to compensate for the jack being on the bottom of the Treo. Also, the remote could have a microphone and the play/pause button could be the record button when not listening to music!