Hi, Joe.
If you want to use the same drive, you will indeed need to use sparse images, stored on the drive, as described in this FAQ:
http://www.shirt-pocket.com/forums/showthread.php?t=81
SuperDuper! will recognize the drive as FAT32 for storing *images* on, it just won't clone directly to it. So, the method in the FAQ will work. PC won't see an HFS+ drive, so that definitely will not work for you.
Hope that answers the question...