[LAU] Using USB keyboard knobs and sliders in linux

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