Hey,
I know this is a late reponse but I just thought I'd answer your question in case anyone else wanders across this post.
I've tried these headphones the 3 buttons on the remote control functioned like this with the HTC Desire:
+ Button - Did nothing
- Button - Did nothing
Middle Arrow (>) Button - Did answered the call and hung up the call. Stop and Started the tracked in the Music player.
During the call I could hear all audio coming from the other calling party.
However they could not hear me.
These headphones worked very poorly with the already poor radio. - Still looking for an alternative radio headset to act as the phones antenna.
Regards
Mike