You can make a replacement pin from a drill bit shank.
Can you post a picture of the schematic your using or use the one I posted to identify what pin you need.Part 38 in the trigger group schematic. Thats not a bad idea to use a drill bit, I might have an extra that fits.
Those are nice, that detent ball is a excellent improvement.View attachment 851991
There's also this available from Tandemkross, has a ball detent in it to keep it in place. It's in stock at Calgary Shooting Centre for $7