Approval Module in WHMCS

I need Proof approval module integrated into WHMCS where customers can take a look at the PDF proofs, make all neccessary notes for changes directly on a document and mark proof as a [login to view URL] [login to view URL] CHANGES and resend and 3. MAKE CHANGES and process. Customer has to be able to upload files. When a customer orders a Custom Design, they will see ths module as a part of the product details or as a separate menu item. System has to be very simple, user friendly.