I have a headset (Sennheiser PC155- it rocks BTW) with both a 3.5 mm headphone jack and a 3.5 mm microphone jack and would like to use it with my Treo 650. I have tried the PPC 4-pin 2.5 mm --> 2x 3.5 mm. (Built for the PocketPC). Doesn't work!

Has anyone found a solution for splitting the Treo 2.5 mm headset plug into 2x 3.5 plugs? (1 for the headphones and one for the mic?) At this point, I don't even care if the sound patched through to the headphone is stereo or not.