In my defence, this is a third party WSDL and I can't change it. My surname has an apotrophe in it and I know very well how many problems it can cause (have you noticed my login on the left?).
That said, I wonder if this is a bug of JBoss AS or JBossWS. if the specification allows the use of apostrophe in the target namespace (I'm not sure), It should be possible to generate clent and web service without problems. I haven't investigated a lot on this issue so I'm probably wrong.
Thank you very much for the suggestion, I will try it.