Pretty sure that Riivolution, you can use both SD cards and USBs, so I think(Not 100% sure though) that if you put the exact contents of your SD copied onto your USB and run Riivolution, that you should be able to do it that way.
I'm using Riivolution right now and I don't have any problems except for the adventure menu thing. So what I'm trying to do is play Brawl off of USB loader but, I have to use the sd file patch code and that freezes.
So honestly, I don't see how your explanation can solve my problem.