Since this answer is incomplete, I will add this one point. There are little plastic clips attached to the outer door that hold the grate frame in place. If you look around outer edge of the grate frame with a flashlight you will see them. If you unhook these clips from the grate frame, the grate frame will, not easily, pull away from the outer door and that will expose the handle screws. Be careful, because the grate frame will swing on the door hinges, but there is nothing holding it in place once you unclip it from the outer door so if you let it hang there while you work, it may fall off.