[Brad]

In vBulletin the salt is generated like this;

From the file /includes/class_dm_user.php

PHP Code:

    /**
    * Generates a new user salt string
    *
    * @param    integer    (Optional) the length of the salt string to generate
    *
    * @return    string
    */
    function fetch_user_salt($length = SALT_LENGTH) // Note; by default SALT_LENGTH is 3
    {
        $salt = '';

        for ($i = 0; $i < $length; $i++)
        {
            $salt .= chr(rand(32, 126));
        }

        return $salt;
    } 


Depending on how your current system works you may or may not need to reset the passwords. Can you give us some code to look at?

Once you get your custom registration system hashing passwords like vBulletin all you'll have to do is get that data over to the vBulletin database (pretty easy task).