It should be doable, but it will require some programming on your part.  If you look in web.config, you'll see that ElectronicFile.aspx has ElectronicFileHandler set up as its handler.  What you would do is write your own HttpHandler, and set that url to map to your handler.  Your handler would accept the request and look at the URL parameters for docid and such.  You could either send the mail right away, or preferably write the information to a database for asynchronous sending.  After you do that, you can Transfer() the request to another url that you have set up to map to ElectronicFileHandler.