An instant setup script needs to be written around WHMCS billing system:
[url removed, login to view]
When a new order is placed and the invoice paid, the script needs to update the WHMCS product page. All the details are to be put in manually before hand in batches.
It must be able to mark off details it has already sent as not to duplicate or send the account to more than one user.
Please let me know if you need more info.