Ok guys, I put on the super magnifier and figured it out. There is a 3/32 allen screw that is accessed through the middle of the spring. Once unscrewed, then there is a threaded retainer that must be removed. This must be done with a retaining ring tool, or something very rigid because the retainer has been secured with Loctite or a trained Gorilla! Now that I think of it, I remember seeing the process on Don's mod site, relating to the E series which is put together the same way, duhhhh.....
Next, remove the aluminum button from the tail cap, drop the Kroll mod into the SF body and attach the cap makeing sure the rubber boot is centered. WOW! this works great. Another spectacular creation from McGizmo. Very Happy! and as usual, great product and delivery from the Samich Shop! Thanks Guys, it makes being in the dark worth while.