在php中上传文件时，Charset会崩溃

We have a HTML form and it contains textboxes and file input. We are sending form with Malsup's jQuery Form Plugin. When we are posting without file, there is no problem in the charset like this:enter image description hereBut when we want to add file via Browse... button and post then, all of form values are broken down like this.enter image description here Our all encoding is in UTF-8 format. When we use iconv like this, iconv('UTF-8', 'ISO-8859-9', $_POST['value']);, problem fixes. But you know, it is not solving problem, it is only covering wound with fluster. In the local server, there is no problem uploding file. But when we use iconv in local, charset is broken down too. I don't want to use a function like this:

function piconv($value)
{
    $local = (in_array($_SERVER['REMOTE_ADDR'], array('127.0.0.1','::1'))) ? true : false; 
    if (isset($_POST[$value]))
        return ($local) ? $_POST[$value] : iconv('UTF-8', 'ISO-8859-9', $_POST[$value]);
}

I did not manage to solve the problem. Please could you help me?