If you are concerned about the cabinet side not being strong enough, use 3/4" MDF plywood instead of paneling. You would have to put an edging on the plywood, but it would beef up that side. It would also give more for the cleat to attach to. Another way, it you don't like the plywood idea, is to install a cleat inside the cabinet in line with the one outside and screw the two of them together. This will reinforce everything and should do the trick. Use wood glue along with screws. Have a damp rag handy to wipe off ooze out.