Using Forms Based Authentication in ASP.NET for Static Content (Doc Fi

Scenario: You want to implement Forms based authentication for ASP.NET web application, and you have certain document/PDF files which need to be protected. It should be such that even if you try to browse that .doc file directly, it should take you to the Login Prompt OR it should simply deny access to the file. In a nutshell, only the folks who have provided the UserName/Password should be able to access the static file.