Ah sorry, that was my reply you were questioning. Since your problem was the content type header being provided, all I'll say in my defense is that it is your browser that is at fault. application/zip should be recognized as a zip file and handled accordingly. application/octet-stream is more for .exe files, but will also work for this situation. Just to be curious, what browser did you use that printed out the zip file contents in the client window? I tried it in both Opera and Internet Explorer and it worked fine for me :)