[emacs-w3m:11423] Content-disposition: ... filename... ignored

MediaWiki ( put some titles in the box on
http://radioscanningtw.jidanni.org/index.php?title=Special:Export )
sends headers
      Content-disposition: attachment;filename=%E5%8F%B0%E6%8E%83-20101118025928.xml
      Content-Type: application/xml; charset=utf-8
but emacs-w3m ignores them and plasters the xml all around the buffer as
if it was HTML, instead of treating it properly as a 'Download'. Maybe
it was the little d in disposition?
At least with my http://jidanni.org/comp/configuration/.emacs-w3m .
On the other hand Firefox of course properly asks if it should save it in a file.

Also,
http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=googleearth-package-0.5.7.patch;att=1;bug=596423
has
        Content-Disposition: inline; filename="googleearth-package-0.5.7.patch"
        Content-Type: text/x-diff

Well, emacs-w3m does ask about saving it in a file. But the filename it
offers is "bugreport.cgi'!! Of course Firefox naturally gets this one
right too.