In former life... (read as "many years ago"), I fabricated a custom made parking brake attach bracket for the firewall. I had already drilled and installed it. Now I started figuring out how to route the CT-cable  to operate the parking brake and found that I would have to fabricate some additional angle construction to hold the cable in place with an adel clamp above the parking brake valve.
As I went through my stuff I stumbled upon a box I had bought a very long time ago. It contained a parking brake installation kit with holding adapter and an arm mounted to it which can hold the adel clamp.

So drilled out my old custom made bracket and looked for a suitable place at more or less the same location to install this new bracket. I will close the holes in the firewall from the old one using some "rivets to nowhere" and seal them off with some additional 3M firewall barrier.

In this session I just drilled the adapter to the firewall and installed the nutplates on the inside of the bracket that will hold the parking brake valve in place.
As the mounting bracket is in a different location, I will also need to remake or adjust the aluminum brake lines that run from the firewall penetration point for the brakes to the parking brake valve.