[donv]

Here's what resulted. At work we happened to have some pieces of galvanized sheet metal that came in as shipping braces on a computer rack enclosure... taking advantage of that ready stock, all that was left was some hacksaw work and some bending and drilling to get to this. Locknuts and socket cap screws secure the plate to the seat through the existing holes. Ended up with just holes instead of slots in the plate for the screws and with luck it aligned perfectly. The bracket came with the Halotron (Halon replacement) fire extinguisher, it mounts to the plate with locknuts and screws.