This probably won't help you, but it's all I've got. On my 17 1/2SB the awning screwed into the floor system, which on mine was very rotten.
Reinforcing would be difficult unless you have access to the framing either by removing siding or by inside access. If the mounting points are behind beds/booths/cabinets you could possibly install a block on top of the floor running from one stud to another and move the mounting point up to that block. Would need to fill the void between the block and siding to avoid crushing the siding. Not sure that all makes sense.