Can anybody give me a step by step to link my keyboard volume knob to a pitch knob on fl studio?

Does anyone know of a good source for decent priced knobs (non-metal) to outfit an entire mixing console?

I think I've about covered all that are listed in the distributor catalogs (print and online) (Mouser, Allied, Newark, Peerless, State, etc.). And I've contacted a most all the manufacturers I can find on the net that are not in those catalogs.