Instead of the WSDL file generated by "wstools" I used the WSDL file in server\default\tmp\jbossws: Eclipse' Web Services Explorer works fine.
Thus there seems to be any difference between the output of wstools and the WSDL file generated at runtime...
However, using JAX-WS RI for the client still fails.
This following namespace declaration is not generated by wstools
After fixing this defect I had no problems in generating a client using JAX-WS RI !!!