Well if you have only one cdrom and you use it too boot Knoppix then I'm afraid you're out of luck unless you get the newer verison w/ the 'toram' cheat code. BTW- it is impossible to mount a cdburner but you can mount a file system that's located inside the cdrom drive. It is however unnecessary and impossible to mount a blank cd. Why? No filesystem to mount. Anyway, if you want to mount a drive you just do this:

mount /dev/? /mnt/?

That is to say "mount /dev/(whatever) to mount point /mnt/(whatever)

OK ok something a little more sensible:

mount /dev/scd0 /cdrom