i tried to get the crack to also work but not being programme minded failed to do so.
after a little searching i managed to find this
<a href="http://www.alien-aus.com/multicoverprint" target="_blank">http://www.alien-aus.com/multicoverprint</a>
makes the same perfect copies but as of yet - no shareware.. done about 100 covers so far.
also no need to know the sizes, nice little tabs at the bottom for each size case.
hope it helps