Confirmed issue as reported. There is an upstream patch available to support the newer msdos parameter as well.
http://lists.xensource.com/archives/html/xen-devel/2010-10/msg00077.html -M -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org