remote upgrade of a dom0

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

I have a remote machine running 4.0 and xentools/xenkernel 3.1.4.  I'd
like to upgrade the dom0 to 5.0 and xenkernel to 3.3.1nb1.  To
complicate matters, the two disks are RAIDed.  The question is how to do
the upgrade safely, given that the machine in question is 400km from
here.

I have remote serial console access; there's also a power bar for
giving the machine a good solid kick in the reset button.

Thoughts?

                --Steve Bellovin, http://www.cs.columbia.edu/~smb