If your shotgun doesn't have a rail (Picattiny or Weaver) you should attach one to the side of the Forearm (like I did to my Reminton 1100 in this post about the Slarforce L-2 flashlight)
link.
http://www.thefiringline.com/forums/...is#post3873744
The Picattiny rails ara available from Bravo Company and Cheaper Than Dirt.com. you should attach them with screws and poxi glass.
Or use a Weaver rail such as the one for the Marlin 336 rifle.
After that any Weaver or Weaver style ring will fit in the Surefire body or equivalent (such as the Solarforce light)
Remote pressure tape switch can be found at Cheaper than Dirt (AIMSHOT remote switch).
Other mount are available. here is one that permits you to move the light laterally.
http://www.patriotoutfitters.com/scr...productid=5382
Here is a picture of my 1100 with light installed
Cheaper Than Dirt also sells a UTG mount that attach to the barrel, it have 3 sides Picattiny rails so laser and more can be attached.
Cheers
Black Bear