Here's some possible sources.
Gun Parts Corporation sell parts, but the pins are listed as out of stock:
http://www.e-gunparts.com/model.asp?idDept=73
The current importer of Tanfoglio guns is European American Armory (EAA).
They may have parts:
http://www.eaacorp.com/
You'll do better actually calling them.
Jack First is a great parts house:
http://www.jackfirstgun.com/
You HAVE to call here.