Please see attached image:
 

 
I've got myself an M-Audio Axiom Mk2 Controller Keyboard. I've managed to set it up for the basic stuff. With the knobs on the keyboard I can turn the mixer faders up and down. But I have no clue how to change the channel selection (the red bars) via keyboard. I'd like to shift it left or right with some buttons on the keyboard. How do I do that?
 
Thanks!