I'm working on the same issue right now. I'm leaning towards using the 2 spare strips of ABS that come with the FX kit as a second belt of sorts. I'm thinking about attaching (snaps) the strips to both sides of the inside ab plate just under-lapping the outer belt, wrapping it back around and velcroing/snapping in the back. The lower back/butt piece would then go over this inner belt, and the outer belt would then be fastened as normal.
Does anyone see any flaws in this method that I'm missing?