I need MPC-2500 + M-AUDIO Pro-Keys 88 help???

How can I use both of these on Pro-Tools 9 at the same time? Is it possible I can use both of these with just a Tascam US-122L USB 2.0 Audio/MIDI interface? What Do I need to buy? And where do I need to go on the program itself to enable these instruments? Sorry for the stupid questions, Im still learning....

Use your computer as the master. Have MIDI going out from both the MPC and the keys.

If you need data from your mpc/keys to send to the other device then you will have to setup midi going out of pro-tools and into your device.

The keys have a dedicated USB port for communication, while you will have to use MIDI cables for the mpc 2500.

If you are going the route of having your mpc/keys talk to the other device, they you will need to route all of the sounds together (either through a mixer or using your PC as a mixer and having the sound out into your soundcard).

So I guess you need to clarify if you are using your MPC/Keyboard as a midi controller, a sound module, or both.