The customfields on the page are not ordering by order field ( using 2.0.20b release), only by an id. I think, it isn't correct. A fix of that problem i found here http://forum.virtuemart.net/index.php?topic=90362.45 (someone wrote, that it have been fixed in the previous releases, but it isn't in latest) , posted on that topic too, but the chances, that developers will see it, are bigger in this section.