first off. what is that? I see threads, a button, and a potentiometer. I however don't see anything identifying this particular thing. Oh and a spring. Forgot to mention the spring, oh and the screwdriver. IT'S A SCREWDRIVER. No you can't mod a finger. It'll only ever be a finger. (damn don't I think I'm funny!!)
Seriously, tell us what it is, where you got it, show us teh other side, a little bit more information is necessary for us to determine if this is modifyable or not. Based on what I'm seeing so far your already doing the mod with the screwdriver and wasn't sucessful hence the reason your asking here.
My guess by thread title and the pic is that it's a Kaidomain or DX (CR2 powered) laser. There's not enough info to go by, so it will be hard for anyone to offer any intelligent suggestions. You may, however, receive many sarcastic suggestions until you provide more detail.
I think that is the perfect answer, turning that pot does jack-al, well done djeeper, claim your prize from the opening poster....if he ever comes back :