The docbook XLS could be downloaded from the following link:

http://sourceforge.net/project/showfiles.php?group_id=21935

Unzip it to something like: c:\docbook\docbook-xsl

We have to make one modification to htmlhelp-common.xsl; open the file and search for “[FILES]”; right after this line include a line with the following text “img/nav/*.gif”. This is necessary so that the htmlhelp compiler can search the images for navigation in the given directory.