Paging doctor E. Lectronics! Here's the catch (it was discussed in a thread before, but i can't really blame you for not findinding it, neither can i): there's an extra pin compared to non-mic headphones, which has do to with the microphone (obviously). The thing is there's either no standard for which one that is, or nokia threw it out and did it their way (which is understandable considering the dual nature of the jack).