to be honest, i am unfamiliar with XP-30, yet I am familiar with combining your PC with some equipment. To be honest, I ditched CakeWALK as soon as I could. I cannot figure out HALF the times it hangs up and the instability of it just PISSED ME OFF. It's UNPROFESSIONAL.
My question to you would be what you need. You really have TWO choices of what you need. (1) is using Cakewalk as sequencer through your MIDI support. I'm not an expert here, so I will let some MIDID guru explain CakeWALK to you.
Yet if you need a sequencer PERIOD, and you would like to record your own samples live, and then sequence them, I would recommend using BUZZ: digital COMPOSER. It's a tracker-based program that allows you to programm music, yet I tried using at as a sequencer with my YAMAHA Clavinova and even used it with guitar-recorded samples. It works perfectly, even though programming all effects may appear a bit cumbersome for you in the beginning. The full version of the program is SHAREWARE, which means that after a few minutes of downloading, you can start sequencing/programming music. I haven't seen another instrument HALF as powerful as BUZZ. The webpage is at:
http://www.buzz2.com/ I am not trying to push the program on you. It IS another way to solve your problem, at least the way I see it, because I HATE CakeWALK. Overall, I would see some other programs, yet if you are sued to working with your computer when creating your music, BUZZ is the right thing for you. I'd say GRAB IT. But again, if you are willing to stick with CAKEWALK, I'm sorry I can't help you.