JBossWS comes with JAXWS tools for doing code-first and contract-first development, see http://community.jboss.org/wiki/JBossWS-JAX-WSTools
The wsdl you find in server/myserver/data/wsdl is the actual wsdl the server is using, as per JSR109 requirements. However, you can provide your own wsdl within the deployment and reference it in the @WebService annotation, see JAXWS spec / documentation.
Finally, consider having a look at the JBoss Tools project, as that offers Eclipse facilities for using the jbossws tools (the axis based stuff is not good at all with jbossws).