we don't have a tutorial for implementing unique salt strings.
it could be dome by setting a session on the registration page to set the salt string, add a column to the users table to store the salt string and use the session in the webassist/security_assist/wa_securitykey.php file.
in the login page and other pages that use the password, you would need to have a recordset that used the email address to lookup the salt string and reset the salt session variable