Client Invoice System

i need a simple and easy on-line php client billing system that allows to bill clients and accept paypal and 2checkout. What i looking for is something like this (let's say a clone of this): <[login to view URL]> but with helpdesk to comunicate with customers. Customers should have the way to download the invoice from ther control panel in .pdf I should have a nice design and language file Script should be coded in php (compatible php4/5) I do not need color/scheme modification Source code becomes our intelectual property and cannot be sold to anyone else. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). * * *This broadcast message was sent to all bidders on Saturday Oct 20, 2007 5:58:30 AM: this is just an update to this project: Script should be coded in php (compatible php4/5) Source code becomes our intelectual property and cannot be sold to anyone else. * * *This broadcast message was sent to all bidders on Saturday Oct 20, 2007 10:30:58 AM: i have forgotton to mention 1 thing on project description. What i need i a way to send an e-mail to all clients. It would be good if there is a way to make groups to send message A to group1 and message B to group2 ## Platform linux