Try a wobble extension on your ratchet. It's at a funny angle but using the wobble extension may help. That's the first thing I reached for so I don't know how it would be with a regular one.
Edit: sorry you meant the cover to the bolt, not the bolt itself. I used a mini pick from harbor freight. The set was on sale for I think $1.99. You could probably almost get away with a jumbo paper clip bent the right way.