Headlight will not unlock seems stripped

[cmccloud]

I am trying to change some bulbs out on a 1999 Boxster. Removal tool was missing from tool kit. Using a 5mm nut driver bit. There looks to be a plastic six sided slot for the bit to fit in but when turning it to unlock Headlight it just turns without much resistance. It does seem to loosen a bit when going in the counter clockwise direction as instructed but does not fully release headlamp unit. Is there another way to release the Bow clamps from under the wheel well? I am guessing that the prior owner must have stripped the locking bow clamp because this is the first time I have had to change a bulb needed for an inspection. I have searched everything I can think of trying to find a fix for this short of taking it in to dealer (which I don't want to do $$$$$). Any help would be GREATLY appreciated!!