$config['file_name'] malfunction

[eluser]Maglok[/eluser]
I've worked with the upload class before.

I have some code, where it uploads just fine. Due to the nature of the image though, I want the name to be the username (which is unique).

Thus I tried to use $config['file_name'] = $username

This doesn't seem to do anything. Some searching on the forum gave me a few threads where the problem was never really anwsered.

My config:

Code:

$config['upload_path'] = base_url() . 'uploads/';
        $config['allowed_types'] = 'gif|jpg|png';
        $config['max_size']    = '100';
        $config['max_width']  = '1000';
        $config['max_height']  = '1000';
        $config['file_name'] = $medewerker->solisid;

I have also figgled a bit with the $config['overwrite'], to no avail.