When I first looked over the cavity, I had no idea how it should be mounted. Naturally, rather than ask the maker and risk looking silly, I improvised (also, when I get lost, I don't ask for directions until I run out of gas).

So I made a mounting "saddle" that would secure the unit in the proper position on the chassis. I machined a piece of aluminum and a brass strap for this, but one could always use another method; just take care not to obstruct the vent holes, feed-through caps, or the controls.