Originally Posted by givmedew
You can drill a hole above the screw to make a proper notch for it or you can just drill right through the entire top of the screw or you can drill out all the rivets and then replace them with self tapping sheet metal screws.
If you are going to drill through to make a notch our I recommend you use a very very small drill bit to make a pilot hole and probably use a size in-between the final size as well. If you just start with a large bit it will just walk all over the place and since you are on the edge of the metal you probably won't be able to make a hole unless you start with a tiny bit that goes through without being to close to the edge.
I would choose this method, it look cleaner.
Or if you don't mind,cut a notch for easier access to the screw.