Removing brass(?) ring holding in driver?

I've got an Ultrafire clone of the Sipik98 (thread here), dedomed and working pretty good. But I can't figure out how to remove the driver for possible future upgrade (eg. 3+ Amps to drive a sinkpad'd dedomed XM-L2 or XP-G2). There's a gold-coloured metal (brass) ring holding in the driver, but I can't figure out how to remove it; don't know if it's screwed in, pressed in, ...? There's no indents/grips on it to either screw in or out with, nothing that jumps out and says "pry here", etc.

Here's a pic; anyone come across one of these before?

JUST A GUESS, but it looks pressed in to me. I don't see any evidence of threading. If it were mine I would desolder the spring and try to pry under the ring to see what comes loose.

I'm in a similar situation and have tried prying mine out but no luck. I'm wondering if mine is epoxied in

I've had to tackle the same issue when mod'n a UTG IRB LED reflector assy. What I found was they were being retained by solder from the regulator board that cant be seen from the backside. I had to use a heat gun on the brass retainer to melt the solder and then pry away that brass piece. Whether solder or epoxied I would try heat.