I've checked most of my "saved info" and don't find that particular comment. The order of installation isn't mentioned in the up-front articles on dual boot, but they appear to ASSume that your older Windows will be installed and you're adding Vista.
Must have been a Tech Net of Dev Net article(?).
We probably have at least 30 or 40 "Microsoft Press" books from "professional contacts" where they sent us "courtesy copies." I've yet to see one worth buying, simply because the authors all assume that everybody has the same setup they have, and they NEVER define what machinery (and often not the programs) they're talking about. I makes it very difficult to make sense of what they say - - but techies don't generally make good authors to begin with, and when they make managers out of them the full lobotomy kicks in.