"frenching" my license plate

hey, im thinking about shaving the back of my trunk in my 94 civic and mounting the license plate inside of it. how would i go about doing it? do i just take the license plate lights out and weld a piece of sheetmetal over that whole area? or do i need to fill it in solid? or what do i do? any help would be appreciated. and also, if anybody has this done to their civic post some pics!