I have wired headphones for my HTC Magic which only produces sound - it does not have a microphone. However, my phone thinks it has a microphone, which means if anyone calls me when I'm listening to music, they can't hear me as the microphone on the phone is disabled.
I planned to get around this by trying my hand at android development and was frightened at how quickly I could get a working GUI together to control this. However, when I browsed through the SDK for a means to write the back end to independently control audio devices (e.g. Enable headset speakers but enable the phone's microphone), all I could find was android.media.AudioManager which only seems to allow me to have the headset either on or off - it doesn't let me mix and match audio sources.
Does anyone have a workaround for this or have I missed something? :-s