I don´t see what the problem is. Unless you hold a special approval, your B1/B2 or C approval only covers you for work as desdcribed in the manufactures Maintenance Manual incl. SRM and WDM, but NOT vendors Overhaul manuals, Seats, Galleys and certain other cabin equipment may be allowed, and that in my opinon makes it very simple, if it is not in the MM, you are not allowed to do it. Brackets and other ´hardware` you need an engineering drawing to comply with.