If there is no "backing", just place the top handle mount where you want it, and drill holes clean through the "wall".[Lower mounting bracket will not need this, just drill small pilot holes and screw into wall. this lower bracket does not take the brunt of the force.] Now make a nice 4 inch square block of OAK, round off edges, stain and varnish, and have someone hold the block over the holes [inside] . Screw in through the mounting hole on bracket with lag screws. Make sure they are long enough to go into the Oak block, but short enough to NOT go through the "block". Then use any hook you prefer, mount to block, and hang the flashlight, or keys. Also, remember to sand down the handles bracket "edge" that prevents the handle from swinging "open. Pranksters have "closed" the handle, at night, against the door, while you are inside. When you try to open the door, the handle prevents the door from opening, unless the edge is filed off. Newer grab handles may have corrected that problem..