Audiovox SMT 5600 / SPV C500 (HTC Typhoon)

I just received the Sennheiser MM50 ear bud head phones and love them! However, only the right channel works and Sennheiser customer service says they are not compatible. I have the head phones that came with the phone (that are just about worthless in my opinion) and would gladly snip the 2.5 mm plug off them and use it on the MM50's but I have no idea about the wiring configuration. Anyone have a suggestion?

Thanks a lot!

Scott.