I'm currently having an issue with a field I modifying (bank_account_type) to show specific options I want displayed during checkout. When new fields are added, and changes are saved, returning to the same window reveals that the previous options are duplicated while the latest addition is missing.
This issue was originally posted here ...
http://forum.virtuemart.net/index.php?topic=36561.0 (http://forum.virtuemart.net/index.php?topic=36561.0)
... and has been unresolved for quite some time.
I'm working work Joomla 1.5.9 and Virtuemart 1.1.3 stable
In the link you have posted there is a suggestion to try latest nightly (https://dev.virtuemart.net/cb/proj/doc.do?doc_id=1328) build, did you try it?