If you are going to certify a component "off wing" and issue form 1's for it, it needs to be on your capability list as your company has to be certified, equipped to a level to overhaul it and can be audited as so.
If the component is "On Wing" and what you want to do is not covered in the usual AMM, SRM, WM, SB's etc, you need to be very wary of doing it IAW a CMM, I don't think you can do this (although I can't find the leg either).
I'd always run it via the Manufacturer via Queery note and get auth from them via fax or whatever to clear your paperwork.
This kind of thing pops up with APU's and engines a lot.