You could call Briggs (800-888-4458) and ask if they have a distributor or sales rep in your area. If you're near Metro Dade or don't mind ordering on-line or by phone, Guillen's Enterprises in Miami should have the assembly you're looking for. Guillen's will ship world-wide and list the "B357104" as:
Product ID: BRB357104 Category: Parts BRB357104 Description: BONE HANDLE 4430/4440 Price: $5.12