MIDI tracks can be opened in any DAW or sequencer made since the beginning of MIDI in 1980's.
Roland and Cakewalk have always used the same note assignments. Yamaha is a little different. So it's a simple matter of opening the CWP, CWB or MID file in X3. Then assign it's output to TTS-1 or Session Drummer. If you have bought X3 Producer you will have Addictive drums.
The Midi track should be by default, channel 10 which will play TTS-1 GM drums.
Session Drummer and Addictive drums need for you to load a drum kit of which there are many choices from Electronic to Jazz kits before you'll hear sound. They are way better than TTS-1 because they play real samples of real drums. ( I still kinda like TTS-1 kick :? )