I've also found DJVUTOY a useful piece of software for manipulating DJVUs. :
http://www.comicer.com/stronghorse/s...jVuToy_eng.zip
is an English version, unfortunately the main site is in Chinese.
With it you can split and merge DJVUs, insert bookmarks and manipulate hidden text by exporting it, editing it then re-importing it. I used an early version for creating effectively a clickable TOC for a number of DJVUs. Documentation is sparse so a bit of experimentation is needed to get the best out of it.
BobC