I have cut a piece of high density foam to fit under the brackets(they made need to be bent to match the limb) then used 4 or 5 "O" rings to hold it in place. The foam pushes back againest the "O" rings. The "O" rings can just be rolled up and the quiver removed and the rings stay on the limb. Get the thicker "O" rings and work the roll tension out of them so they will stay and not crawl.
I have also used clear plastic wrap folded over to the same width as the quiver bracket and do a few wraps stretched around the limb and then stretch wrapped around the quiver brackets. You can tuck the end, use a wrap of tape(camo if you have it), or a rubber band- which will dissolve if in the sun.