if it can be programmed with sysex (most can) you can
use a midi faderbox, like the peavey PC1600 (16 sliders +
16 buttons) or the encore knobby (8 knobs). Both
do sysex, you have to program it (or download a program
someone else has set up, there are a lot for the peavey
and they are still working on ones for the encore) but
that should do it...