AudioMixer (System) not working in win7

I am trying to change the main system volume and have found AudioMixer (System) but when I change the volume on it I get no change in system volume.

am I doing it wrong or is there a bug

EDIT: I am on win7 64bit beta31.2 - 32bit

ja, seems the underlying api has changed. for me it only always changes vvvvs volume. this used to work in XP (or was it 2k?). so now probably your best bet would be to find a c# way doing this and write a line of code. or 2.