Davy,
I think you'll find that the constituent parts of the safety are the safety switch block, a wee spring, a small ball bearing, and a little grub screw (if i remember this correctly). The safety catch block goes into the trigger first, then the ball bearing, followed by the spring, and then to close it off, you insert the grub screw.
That was the case with my mate's S410, but his was an early version (his one has 3 trigger sears, and is pre anti tamper, if that helps you?).
Hope this help you out some bud?
Regards,
Grim.
thanks grim i will look into it
regar