Change volume of bluetooth headphones

[fra.achille]

I'm doing an application that needs to play sounds and change volume.
If I use the waveOutWrite() and waveOutSetVolume() functions everything works with normal headphones but when i use the bluetooth headphones the waveOutSetVolume doesn't work.
Does anybody now how can I change the headphone volume via software? (I'm using hp ipaq bluetooth headphines)