Here is a shot of the two Rotopax. The yellow one is screwed thru the wall right into the mount. for on the other side is a storage box where the legos are kept, so that was easy.
On the outer flap for the gas can, I added a piece of hardwood, glued and shallow screwed to the inner flap wall, then I screwed the mound and its base to the hardwood, with piloted flathead wood screws, wood was HARD, maybe a little overkill, but I’m not sure what exactly that flap wall is made of.
Here is a better shot of the gas container. You can see that it tucks right into the existing framework of the underflap. The hardwood board runs horizontal and is screwed in to the vertical pieces on both ends, and is glued and shallowed scewed to the innerflap.