I'll try to answer your questions by telling you how I solved this exact problem. This is probably more info than you need or want, but I just want to cover everything I ran into doing this. I have the 880, the JVC CD-RW that Roland supports, and a PC with a Sound Blaster Live (full, not the value version.) I can burn CDs right from the 880 using the CD-RW hooked to the SCSI port, or use the digital Out on the 880 to the digital In of the SBLive card to record into the PC. I use Soundforge, but any wav editor/recorder will work. Wav files (16-bit, 44.1KHz) are what turn into CD tracks when burned, and that's what you will be recording into the PC from the 880 most likely by default. You could use any decent sound card for this, but the SBLive is the cheapest I know of with digital I/O that works good enough for things like this. You can try going from one of the the analog Outs on the 880 to the line input of you current sound card if you want. It was way too noisy for me when I tried it, but it won't cost you anything to try it. If you are buying a CD-R to work with the 880, make sure it's the one (or possibly two now) that Roland supports. Otherwise you can forget hooking it right to the 880 SCSI port and getting it to work. The only reason I would buy the Roland CD-RW is for backing up tracks from the 880. If you already have a method for this, or plan to backup the 880 another way, then save some money by getting a CD-RW for your PC.
If you want to try recording to CD directly from the 880 via the audio outs, then you are talking about standalone CD recorders that are more like the size of a CD changer, and don't require a PC to work. I've never tried anything like that so I won't confuse anyone by pretending to know if that would actually work or not.
The best solution for me has been to record the wav files into the PC from the 880, either one track at a time into something like n-track, by doing submixes into a PC multitrack app of several 880 tracks (works well for combining viritual tracks of multiple layered vocals into one track), or for running the entire mix into a wav editor for normalizing before eventually burning to CD from the PC.
If you do want to ge the Roland CD-RW and burn CDs directly from the 880 SCSI port, you have to mix everything down to two tracks and then the 880 will burn those two tracks as stereo on the CD. The whole process is detailed in the CD-RW manuals, I'm just letting you know that it can be a difficult and time consuming tasks if you have multiple virtual tracks going on all 8 channels of the 880. After doing this twice I started looking for another method to burn songs to CD, and now I move everything to the PC for final editing and burning.
Good luck and post back how things go if you get a chance.