Custom PHP Script for Selecting and Printing PDF Documents

My company is bidding out a project to build a custom php script that will allow a user to select one or more pdf files from a library of pdf files, and merge them together for print or e-delivery. We will supply this API to ease development: [login to view URL] demos os pdf merger api: [login to view URL] Basically, this site will be akin to a shopping cart where users can search through documents, select the ones they want, and when they "check out" they will receive a merged PDF, containing the selected documents, a few static pages that would merge with every document, and a title page. THE SetaPDF API allows for all of this to happen, and we basically want to incorporate into an existing open-source script such as zencart or oscommerce, or a CMS such as drupal. One note, we would not be charging users to do this, so there is no e-commerce integration. quick overview of how application will work: -backend admins will upload pdf's of articles -articles are searchable and categorized -end user will choose categories and/or search by keyword -applicaple pdf's are displayed for option to add to final pdf -end user chooses which articles he/she would like and presses publish -end user given option to e-deliver published article to other people in addition to him/herself -end user receives pdf as a download or in email, other users are stored as that person's personal network to receive journals at a later time