Yeah which is why I said you would need a "go-between" I.e if your using X, use the Y save with a .3ds copy of Y and transfer Pokemon to a friend, then have your friend transfer them to your X save
Thanks. From what I've read, the savegames would work if I my ROM was .3ds instead of .3dz. I want to play online, so I will sacrifice my progress and start a new game with the 3dz file.