Auth DB Newbie question

Hello, in line 193 of Auth/Container/DB.php one can read:

        /* Include additional fields if they exist */

This works fine by putting the following in the auto-prepend-file: $params = array(

            "dsn" => "mysql://$user:$pass@$host/$db_name",
            "table" => "users",
            "usernamecol" => "u_username",
            "passwordcol" => "u_passmd5",
            "db_fields" => "u_id"
            );

$query looks like: SELECT u_username, u_passmd5,u_id FROM users WHERE u_username = 'WhatTheUserTypedAsUsername' Also $entry[$this->options['db_fields']] has u_id as value. Now my question: Can this additional value be accessed somehow, which in my opinion would be quite useful. Florian