Contract/Document printing and management System

I would like to have a script written in PHP to help with the fulfilment and management of contracts online. The script will need a user management system with secure login. New users will be allowed to register and sign in. I would like to include a payment module so I could accept payments via paypal and direct credit card payment ([login to view URL] and/or 2co) and the payments would be monthly recurring payments. They payment system must be secure and be able to utilize a SSL certificate. The script basically allows a user to upload blank contracts and then when a sale is made one would login to the site, enter the customers information, the item purchased, and the script would then fill in the contract and allow it to be printed (the contracts will be designed in HTML with placeholders for the variables so that they are printed correctly) and then saved on the server for future lookup. You can also look up old contracts by client name, product name, phone number, etc and re-print them lateron. Also when viewing a client account, you can view all of their purchases/contracts at one time if they have multiples. I have an example of what I am looking for. I basically need a clone of this script but with the registration/payment system added to it. Perhaps a design including some AJAX functionality to make it more modern as well, although that's not a necessity. I will need a backend administration area to handle tasks like that as well as other general admin tasks. For security reasons, the administration area should be in a remote location, or even on a seperate domain on my server. I wouldn't want someone to gain access to the admin area by guessing what folder its in and using methods to crack passwords. Either that, or a PHP-GTK script running on windows that I can use to handle the administrative duties of the site (thats probably overkill but if anyone can do it I wouldnt mind). I would rather not post the link and login info for the demo script publicly so PM me and I will show you the site that I want to clone. Thanks!