Automatic facebook call-to-action creator

With facebook Graph API, I want to create a PHP page that will allow to create a call-to-action button on a facebook page. So everyone will be able to visit this page and add my call-to-action button on their facebook page. For this project, the call-to-action URL can be [login to view URL], and the button can be "Faire un Don" (Donate). If the button already exists on my page, can the procedure override it (for example if the URL is different)? You can see a picture of a button call-to-action created manually in facebook.