#37 wrong character in mail

[adwin1]

The soupermail is working just fine. Mails are send, no problem there BUT
Character like ç ã and í are changed into :

ç = ç
ã = ã
í = í
For example Petição de reserva becomes Petição de reserva in the mail

At the site it looks all right, but when people recieve a mail all characters are changed
How can I solve this ??