Apple Logic Pro /LogicExpress Discussion

Hey guys I'm still a rookie on Logic 7 but so far I'm having a blast.  So here's my problem.  
I'm trying to control my MPC 2000XL with Logic--I wanna use it like I would any sound 
module (e.g. Roland 3080, Motif Rack etc).  I just want to be able to trigger the sounds 
that are assigned to pads in the MPC, using my USB controller.

I have everything hooked up to my midi interface.  I can record midi into Logic by hitting 
MPC pads.  But nothing plays back.  I want to be able to do the opposite.  Record midi data 
and have that data play through the corresponding pads on the MPC.

Does anyone know how to do this??  I would greatly appreciate it.

Selwyn.