Unity - Using WWW with latin characters

I'm using WWW to send some info to a .php file: name, lastname and scores.

string post_url = addScoreURL + "idfacebook=" + idfacebook + "&country=" + country + "&name=" + name + "&lastname=" + lastname + "&score=" + score + "&coins="+ coins +"&hash=" + hash;
    Debug.Log (post_url);

    WWW hs_post = new WWW(post_url);

But I'm having trouble with latin characters. My brother was testing and his name is "João". I saved the data received:

http://myurl/addscore.php?idfacebook=99999999991&country=BR&name=Jo�o&lastname=B&score=68941&coins=621&hash=d98faf76226debc83f9b9fb8976a5e22

I don't know why, but the hash was different. I think it's because "ã" is collected as �.

Do you guys know how I can handle this?