Ciao Nicole, this is just a shot in the dark, but i was reading your post about Piana di Caiazzo and the only thing that i can tell you is that my boss is from that town and his name is Nicola Mastoianni. I know you mentioned a Mastoani in the posting. he came to the United States in the 60's but his great-grandfather did come years ago. his last name however was dibenedetto. i don't know if this can help you at all, but it's worth a try.
p.s. i found this post because my family came from Caiazzo, which is right next to Piana di Caiazzo. my family names there are Bruno, Cretella, and Squella (probably really Squeglia).