title: Zip Mime Type appears unrecognised
body: <p>I'm trying to return a zip file, as a stream over a browser. This works fine with other types of files (e.g. Excel files) but when I start dealing with zip files I can't get my browsers to recognise that it's a zip.</p>
  
  <p>Both Firefox and IE running on my test machine prompt, asking what program to open the file with. Explorer is set as the default for the zip file association.</p>
  
  <p>IE doesn't report very much back, Firefox however tells me what the file type is a </p>
  
  <blockquote>
    <p>application/zip</p>
  </blockquote>
  
  <p>which as far as I can tell is the correct mime type for a zip file. The only thing I don't have set is the extension, so the file is just called 'Test' rather than 'Test.zip' but as far as I was aware that should all be figured out by the mime type.</p>
  
  <p>Anyone have any ideas on what might be going wrong?</p>