Yamaha DTXpress/DTXplorer/DTXtreme

I have a kit now. I'm getting the typical 'snare's sometimes 
triggered when I hit the hi-hat' and I know there are posts in here 
somewhere on how to fix this and I'm not too worried about it 'cause 
it rarely happens.

However, in the meantime, I don't understand why the following is 
happening:

The volume for the click track does not work properly. When I turn 
the knob it controls the volume of the kick, something it's suppose 
to do after you're holding down the shift button. The volume button 
underneath, which I believe controls the volume of the songs you can 
play with does the same thing. When I turn the knob, it controls the 
volume of the snare drum. When I press shift and turn the volume, it 
doesn't do anything.

As it stands, I have this piercingly high click that just about sends 
me into convulsions, and no way of reducing the volume. 

Any suggestions?