I have a Treo 680 smartphone. The headset that came with it only has a right earphone, and it downright sucks. So I bought a 3.5mm to 2.5mm headphone converter. But when I hook up my earphones or speakers to the phone, it's only mono sound, coming out of the right ear. But the Treo 680 has stereo output capability. Does anyone know how to make it stereo?