I've always liked basic HTML pages where one can upload a document without having to restart the entire application. That's a great practice you have there with general forms. With each session ID, it can cross reference a page in a multi page application with that session ID, so that the user can maybe type it in if necessary, but it should be able to determine that with enough information, like IP address, upload date, browser, OS and so on. But the most accurate session would be within the browser so that the cookies for a single application aren't mixed up with another applicant, like a relative, who might be using the Playstation Portable.