Outlook Web Access sends an illegal Content-Dispositon header to Firefox. This is no longer allowed

Outlook Web Access sends an illegal Content-Dispositon header to Firefox. This is no longer allowed in Firefox 8. Firefox 9 will have a workaround for this so that Microsoft has time to fix their software.
See http://support.mozilla.com/nl/questions/895024
https://support.mozilla.com/en-US/search?q=attachement.ashx