How to Restore a tin ceiling?

I'm helping a family friend, she has a circa 1905 tin ceiling, with about a 3'X6' section all corroded out. Can anyone tell me where I might find this patter. I checked a number of sites in home expo, but I can't match the tin. If not, any suggestions on how to mold and cast a replacement section. No luck finding it any any local reclamation places