Trying to maintain one copy of the documentation for multiple versions simultaneously is proving to be a pain in the @ss...
Magnolia is very cumbersome as a documentation tool because of its treatment of "paragraphs", especially with respect to code fragments (of which our docs have many).
I recommend we keep all of the documentation in subversion (using doxia, docbook or similar) so that it is versioned along with the source code. The download page would contain links to the docs along side binary and source distributions. This seems to be how most jboss.org projects are setup.