Yes, I had seen this docu before, but it is outdated. Thanks anyway.
Anyone else could help? How do you people manage to develop your modules with such little documentation?
By the way, I guess I should have posted in the Nukes User forum. My apologies...
there is a basic tutorial on how to create blocks, modules and themes located here: http://www.jboss.org/developers/projects/nukes/tutorial
you can also checkout the code and generate the javadoc yourself by just running the build and executing the correct target.