When you're in a call, spinning the volume wheel works to change volume.
Finding the *right* audiopara.csv file for your device can make a huge difference.
So, if you're running a recent rom, something like
http://forum.xda-developers.com/showthread.php?t=364201
Or maybe
http://mogul-matters.blogspot.com/20...-with-cab.html
I think the first one is correct though. Made a huge difference for me.