I've just begun to use the MMC Replay cart (with an NTSC C64c), with a new 2GB SD card (formatted FAT16), and there's really one thing I'd like to know: I can "mount" a disk to the C64, but is there any way to save from the C64 back to flash? I.e., from within a program I've loaded from the SD card? Or am I still only able to save to my 1541 drive (and transfer to the SD card from C64 at a later time)?
I've already spent a couple of hours on this - I'd just like a straight answer in case I'm meddling in vain

Thanks,
Owen