For interested people,
here is a link http://www.stanford.edu/~mdelgado/jboss/
which explain how to deploy Java Pet Store (old version
:-( on JBoss 3).
You could follow the explanation but I personally prefer
to change the port used by Cloudscape (modify the script to launch Clouscape to add -port 1098), and keep 1099 port for JBoss 3 (no change then).
It's working for me.