The top front screw, when screwed in all the way, locked the retention lever in place, such that it wouldn't budge. When I installed the screws, I tightened the bottom one tight enough that it caused a piece of plastic above the bottom opening for the retention lever to break off.
So, last night, I tried to install the holster onto the included Safariland panel. I was going to sell it, but nobody seemed interested, so I figured I'd keep it and maybe use it, afterall. Flux refunded the cost on my card, but still shipped the holster with the Flashmag. I cancelled the holster part of the order in September, because I decided the set up would really never be much more than a range toy, so I would not likely carry it loaded and, therefore, had no need to worry about covering the trigger. I ordered one when I ordered my Flashmag back in August.