Some pics of my old bikerscout belt and how I assembled it:
I used nylon webbing for the belt, and cotton webbing for the belt box straps. The nylon belt webbing runs all the way behind the plastic, which makes it easier to quickly fix it with gaffer tape if the rivet loosens. ;)
I fastened the cotton webbing to the nylon webbing using heavy duty snaps that are also my way of fastening the thermal detonator. The two pieces of webbing are not snapped together, but rather hammered together inside the one side of the snap. The other part of the snap is on my detonator.
I used Norwegian 1 krone coins as washers. Had to cut them a bit though. They are the best washers, nice and thick, and pretty as well!