[LAU] Using USB keyboard knobs and sliders in linux

[Matt Henley]

I recently got access (on loan) to a Edirol PCR-300 USB midi keyboard.
 When I plug it into the computer it shows up under QJackCtl and is
quite usable as a midi keyboard for the Synths that I use (ZynAddSubFX
and AmSynth).  The question that I have is that the keyboard has a
full compliment of sliders, pads and rotary knobs which I don't know
how to use for anything.  Is there documentation on how to set these
up to control parameters on software such as
Ardour/Rosegarden/LMMS/Ingen?  If so where would i find it?  Do these
controls go to midi channels and can they be assigned to OSC controls?

Sorry for my ignorance, I just didn't know where to start.
Thanks
Matt