title: ASP.NET/IIS: 404 for all file types
body: <p>I set up 404 handler page in web.config, but it works ONLY when extension of URL is .aspx (or other which is handled by ASP.NET).
  I know I can setup static HTML page in website options, but I want to have a page.
  Is there any options to assign ASPX handler page for all request extensions in IIS?</p>