Microsoft Bug come back to haunt?

Ok I posted a mail a couple of days ago about downloading files within PHP. Heres the code I'm using: Header("Content-Type: application/x-tar"); Header("Content-Transfer-Encoding: binary"); Header("File-Length: $fileSize"); Header("Content-Disposition: attachment; filename=$filename"); Anyway the problem is, that if you use IE6 click on the download it pops the box up, "do you want to save or open" it works ok if you click save put if you try open it doesnt open the file properly it adds [1] or [2] etc at the end of the filename. Now I know there was a bug with the "attachment" part of the Content-Disposition in IE5 but this was fixed with SP1. Is there any way of getting around this.