Actually, FDisk in Knoppix wouldn't let access the internal (IDE) Drive either. Again, like I said, the knoppix developers probably did that on purpose (don't think you actually have root privileges by default).
Anyways, form Windows, I used the Disk Management utility from Computer Management and repartitioned the USB Drive, formatting the second partition as FAT32.
Then, I found some EXT2 utilities for win32 here, http://e2fsprogs.sourceforge.net/ext2.html,
and used them to format the 1st partition as EXT2.
Now, what I think I actually want to do is put an uncompressed version of the knoppix CD on that partition but have it still do it's hard detection script so that it creates the appropriate files under /dev and /mnt.
So I will probably end my discussion here and look around on the knoppix threads or the knoppix site itself for more clues.