i'm just getting into cubase and my mpc is in the shop so this is an assumption.
I'd assume you'd use the mpc as a controller midi in, then route the midi out signals back to the mpc. Play your pads on to cubase midi tracks as you would normally with the mpc's seqencer. when you got what u want. record the tracks as audio back into cubase
Once again I havent had the chance to try this. also this is if you want to the sequence to be synced with any midi parts youd want to add.
other than that im sure you could just record it straight thru. if youre using one stereo track just make sure u mix it as well as you can in the mpc before recording it into cubase
if i'm wrong, someone pleez help out. I'm bound to run into the same question when i get my mpc back