We've created this Forum Thread with some workarounds and advice to assist you in publishing you ebook.
Publishing new version without deleting old one
I want to publish a new revision of my book, without having to delete the old version, as I may find I prefer the older version, and may want to continue using it. (Note that distribution is to me only.) I've tried to do this before, but when I looked at the preview, both revisions were included. ???