PHP - Use Dropbox for file uploads in existing site - repost

I have installed the PHP Dropbox library from [login to view URL] and successfully tested the basic functionality on my site. I want to retrofit my site to use Dropbox for individual user file storage. The current application currently uploads local files onto the application's Linux server. I want to modify this so that uploaded files are saved to the individual's personal Dropbox account. In another area of the application I want to access those same files that were saved on the Dropbox account to either view or edit them, depending upon the filetype. Requirements (using library above): 1. Modify the Add Document functionality (shown in [login to view URL]) to use a standard 'Browse' control (not the one currently used) and upload the file to the Dropbox application folder I have created for the user. This requirement includes incorporating providing the ability to create a Dropbox account if not included in the standard dropbox functionality. If necessary, store user tokens in database. 2. Modify the Edit/View functionality shown in [login to view URL] to access the selected file from the user's Dropbox account. Site uses CodeIgnighter as a Framework.