You can do it, it requires a bit of changes in the save file tho. The RD copy has to be USA (or at least I didn't get it to work on a PAL iso) There's an easy way that involves just editing the very beginning of the file. I don't remember it working for me. (the beginning of the file also doesn't seem to be the same) For the other way, you need a blank PoR USA save (just start an USA copy, click yes on creating a file, and you should have your file in (dolphin save)/GC/USA/Card A/01-GF