How do I use midi to control the LP in pro tools 8?

I know this might seem like an easy problem to fix for most users here, but I cannot find a way to make the little phatty play back midi information from protools 8 through an mbox2 pro via usb. When I plug the usb into the little phatty and open a midi track, the lp creates midi information, and the computer also recognizes the little phatty in the midi channel. I read the manual and still couldn’t figure it out, I would really appreciate if someone explain to me how to make the lp play back the midi information.
thanks,
Jacob