You run ROMs on your Acekard. You drag them onto your microsd and put it in your acekard. The games play and save like the actual cartridges.
if you mean save a rom onto the acekard like backup cards you already have, thats not possible unless you have an ezflash cart for slot2
You can backup roms other ways though with usb programs and stuff. you just have to buy those.
To play the roms you have to find them and add them to your microsd, theres no saving needed