Multiple maps on Garmin 800
I'm trying to load a couple of ToastyTalker maps onto my Edge 800 in addition to the base map. I've read that you can have multiple maps on the SD card which you can then switch between - sounds ideal. However, it only seems to recognize map files named "GMAPSUPP.img" so I can only get it to see one additional map. Is that right, or am I missing something? Thanks for any help!