Bill, you could try this place.http://www.e-gunparts.com/model.asp?idDept=143
L.C. SMITH
NEW MODEL HAMMERLESS
Item No. 519240
Safety Spring
Retail Price: $1.70
You don't have a 3 position safety on this do you? Forward on the safety, the gun fires, break open the gun returns to safe, middle position, gun on safe, rearward position, gun fires and breaking open and re-cocking safety does not return to safe, but stays in rearward position.
Also if your gunsmith does not know where to find a safety spring for this. It seems like he doesn't want to work on it, it is time consuming and tricky, but not that difficult. This parts site has been around for a long time, and they do carry a lot of different parts for various gun manufacturers.
Good luck and keep us posted.