I think the main problem is that you refer to the WSDL in the @WebService annotation. wsgen will process the annotations, but at that time, there is no WSDL. Have you tried removing the WSDL reference in the annotation?
Do you have any particular requirements that causes you to use a "manually" created WSDL, instead of using one GlassFish creates at deployment time?
Here is the absolute simplest example I have been able to come up with having an EJB implement a web service:
1. In Eclipse, create an EJB Project.
2. Implement the EJB: