It's actually pretty simple: It sounds like you have the X3 connected properly, you just need to connect another MIDI cable from the other MIDI output of the 002R to the TR-rack. Then it's just a matter of selecting the proper MIDI ports as the input and output of the respective MIDI tracks, and making sure you have the audio routed out from the hardware units into the 002r. You never said what version of PT you are using, but with versions above 6.7 in Windows, there is also another setup step you can go through (MIDI Studio Setup) to make selecting patches easier, but it's not necessary; it just makes things more convenient.