vB4.2.0 change my words with accent

[JoKeRxbLaCk]

Hi guys, i've bought vBulletin 4.2.0 license forum, i've installed it, and because i'm Italian, in my language there's so much words with accent, and if i try to write a post when i public it all the words with accent change in ascii code i think like this: "più" <--- if you can see your board fixed it automatically, why my not? and i've this: "pi&#24'9;"
i've also changed my char set from ISO-8859-1 to UTF-8 and latin1 , but nothing..

How can i fix it?

Edit: my tables is charset: UTF-8 and Collation: utf8_general_ci but if i select utf-8 in language i see a point of question in all words with accent