Ok, here is quick guide how to do it.
Tools:
Drill press (you really need one)
Metal lath (optional)
Dremel, files, sand paper, masking tape
Paint
Orange cat
Bottle of "Russian Standard" vodka
Step one:
Remove buttstock and hand guard. Drill 3 mm or 1/8 hole center of trigger guard slot and 6 mm or 1/4 inch from bottom of rail. Trigger guard is still connected by screw to rail. You really need drill press, you will hit that steel screw while drilling and hole may wonder of.
If you don't have lathe to turn pin, cut off shank from the same drill bit and use it as a pin. It becomes trigger guard front support.
Step two:
Now cut the web. Has to be 13 mm wide to fit plastic mag housing. Do it under supervision from orange cat.
Step three:
Now you need to remove about 3 mm from top to allow screw clearance and a lot for mag clearance. I was cutting a bit, putting all together and so on. Picture for reference what you have to cut.
Step four:
Repaint your trigger guard, let it dry. Heat gun works best. Assemble it all together. Let cat inspect and approve it.
Step five:
Carefully pack bottle of vodka and ship it to my home address