O.K., I found out the following:
Use the java web Services developer Pack 1.6 to generate classed from schema, NOT 2.0 - the clases generated by 2.0 don't resemble at all the stuff written here.
As Sun doesn't make this easy to find (they try to force you to download 2.0, not telling obviously where to get older versions, it's here: http://java.sun.com/webservices/downloads/1.6/
In addition, this tutorial: http://bitrazor.com/content/tivo/hme/howtos/jaxb/index.php
helped me to come fruther here.
Hope this saves somebody some hours of searching and work.
Most important, you'll find the relaxng datatpye lib in the wsdp-shared directory, NOT in the jaxb/lib directory. This was also not easy to find for me.
As the newer version will be what is used in the furture, this article still needs an update, at leat a pointer to mor up to date information.