It wouldn't be too hard to hack. All you have to do is include the following:
1) Check email address with Email address in the Users table or in the Links table depending on where you store the email address. (Use $db->query for the email address.)
2) Then use the sub send_email routine in the modify.cgi script to send the password and username info. (Use $db->get_record based on the inputted email address.)
Regards,
Eliot Lee