You might do a Google search on Walter at Bay Village,Ohio (I think). Or you might contact the Kindigs at Log Cabin Sport Shop,Lodi,Ohio and see if they know if Walter is still active. Their Ph.# is 1-800-837-1082.They might even have a trigger made by Walter for sale.
I used to get requests to make a mechanism for the Germanic locks and I always referred these to Walter and even had him send me some business cards so I could tell others where he was. He is a fine craftsman and the work he did with the Siler locks (rollered frizzen etc) was excellent. He is worth the effort to try and find.
Bob Roller