It might be possible. Dsiware games are stored on the nand, and since Nintendo blocked out almost all access to the nand, there isn't a way to access Dsiware games without a kernel exploit. You are able to transfer Dsiware games to your SD card, so it might be possible to access the saves when they're on your SD card then copy the game back to your system after you've edited the save, but that might not be possible.