MIDI TRACKS?

This one has been killing me for awhile..
I have my MPC 2000 hooked up to a Roland JP 8080 synth. So I record my first little piano melody on Track 1 MIDI 1A of the MPC, no problem, then I want to change the patch on the JP 8080 to a Bass sound, and I want to record this to Track 2 of the MPC, No matter what I try It will not work, ultimately when I change the sound to a bass sound it changes the piano SOUND ON TRACK 1 to the bass sound. How do I keep the piano sound on track 1 while I recording different sounds onto the other tracks. ??

Any solutions/replies to this thread? I've also had this same problem before when using certain synth and i never found a solution...

if the 8080 is multitimbral, you need to set it to that mode, then set the midi tracks on the synth to two different tracks, then tie your mpc seq. to the 2 tracks, bass seq to the bass patch channel, the othe to the other one.