Mailing address of ac Milan: via Filippo Turati3, AC Milan, IT-20 12 1 Milan, Italy.
Mailing address of Brazilian Football Association:
Brazilian future Federation
Rua de Alfan Degas, 70 years old.
Page (abbreviation of page) P.O. Box 1078
20.070-00 1 Rio de Janeiro
Brazil
Be sure to express your requirements boldly in the content, but don't go too far. It is suggested to write ac Milan, where fans are treated better.
What I said above was addressed to the club officials. You can also send it directly to Kaka, so you have a better chance to get Kaka's signature, but Kaka can't see your letter.