I did that, came out pretty good. I just carefully separated the melted together contact points, carefully taped off the desired cut line on the lens and used a carbide cutting bit for a dremel tool on my drill press (set to it's fastest speed) to trim back the lens then epoxied/glued it back together. Of course I tinted the lenses, but you can still get the idea.
http://www.xoutpost.com/bmw-sav-foru...ts-modded.html