I've managed to automate the generation of the SDK documentation
(JavaDoc) for the Eclipse Help plugins. See bug 232547 for more
information. It generates all the HTML files for the class files. It
currently uses a doclet called JELDoclet to produce a xml file of the
java doc, and then creates the rest of the files from there. There is
an ANT build script that does all the hard work, along with two
xslts. Technically, this could also be done if somebody were to write
a custom Eclipse Doclet that produced the necessary files.
Anyways, this isn't limited to just XSL Tools, the same process could be
used across WTP or eclipse projects to generate the appropriate Toc.xml
and corresponding Html files for the help system.