Recording into cubase

I have an MPC2000xl and I'm using a tascam 122 interface and I'm trying to record my drums in cubase witch is on my G4 power book I installed the driver and I select tascam 122 in my sound options but its just recording off my built in mic not from the 1/4 inch cables going from my mpc to my tascam

so whats up??

Nick