Tron,
If the gun has the release hook sear engagement screw (which is accessible through the trigger guard), and you familiarize yourself with how the adjustment screws work by watching it with the stock off, you can do it with the turn of a screw. However, the trigger has to have that extra adjustment screw, and not all of them do. My KS5 "special" had it, but I can't tell for sure if the photo above does. (If my memory serves correct, it's the one Krieghoff expoxies in place from the factory...someone will hopefully correct me if wrong).
Once you use that screw to reduce the sear engagement on the release hook to a sufficient degree, it fails to catch the hammer when set, and the mechanism basically pulls through each time and reverts back to a pull trigger. No need to remove anything. If it's possible on his gun, that's the best way not to lose it...just leave it in.