[LAU] live performance, midi program change from the keyboard

i need to do something relatively simple, but i cant figure out how to do it, or what software i need... basically i have to play a certain song where i need to switch between different sounds (say, a piano at the beginning using qsyinth and then a synth created with zynaddsubfx). I want to be able to switch between one setup to the other quickly, possibly using the program change from my keyboard. How do i do that??? On my keyboard i can create different programs, each using different sounds (patches) and switch between them with the click of a button. I want to use that, but I want to generate the sounds with my computer. I think I need a way to 'map' midi channels to different programs or midi patches to specific programs (like, when i select piano on the keyboard (patch0, bank0) it uses qsynth, and when i select a synth it uses zynaddusbfx). Any ideas? Thank you very much, Alessandro Preziosi