What steps will reproduce the problem? 1.Pair the headset 2.Use the phone to make a call or listen to audio or video 3.Try increasing or lowering the volume using the iPhone volume controls.

What is the expected output? What do you see instead? It doesn't change the volume at all.

What version of the product are you using? On what operating system? 3GS, running 3.1.3

Please provide any additional information below. Is it possible to modify the stack so ppl can gain control of the volume keys in the phone to manage volume on the headset?

hi. BTstack as a Bluetooth stack should be able to handle audio. however, so far, nobody wrote a HSP or A2DP implementation for it which also needs to hook into the OS audio processing.

Check out MusicControls from Phoenix3200 http://phoenix-dev.com/?p=mc he already added support for next/previous song.