dear LILLY:
forget all those before-mentioned programs, they are expencive, complex, and cumbersome.
what you need is a few cables, a WAV EDITOR and BUZZ digital composer:
http://www.buzz2.com/ it's shareware, and it's the most powerful software out there. I have tried recording samples with my CLAVINOVA, and then sequencing them in BUZZ. That would give you versatility to make your own samples, and sequencing them with ease and comfort. the only other thing you need to get is a METRONOME if you want to record beat0mntched samples, OR... if you want to just record a new vioce, by combining two separate synths, each playing the same note, you can do that, too, and record a sample that you can later on transpose using any decent keyboard (i don't know XP-30) and then play with. BUZZ is hard to figure out, and looks very complicated, yet once you figure it out (view the tutorial file that comes with it) you will be able to programm the music, and use it as a tool for producing songs.
If you are still skeptical, my mp3.com website features my songs that I did ENTIRELY with BUZZ. They all were before I got my CLAVINOVA. Chck it out at:
http://www.mp3.com/ilyarostovtsev/ And I would defenately recommend connecting your equipment with your PC. The possibilities afterwards are endless!!!