there are two small black screws recessed in the front of the plastic part on the outside edges, and then there is one screw inside that you have to unscrew as well, through the top of the main aluminum frame. You'll need all of your 5.25" bays to be empty, at least the top half, to get your hand in there to unscrew it.
AHA!
Thanks for that tip. I got the two on the outside, but did not look inside yet.
Thanks