Hi!
Since nothing was said, I assume you want to generate artifacts for a client that is to access the webservice using wsimport.
Have you used the -b flag? The -b flag, after which a JAXB binding file is specified, is available both in wsimport and xjc (the JAXB binding compiler).
Example:
wsimport -b MyJAXBBindingFile.xml MyWSDL.wsdl ...
xjc -b MyJAXBBindingFile.xml MyXMLSchema.xsd
References:
http://java.sun.com/webservices/docs/1.5/tutorial/doc/JAXBUsing4.html
http://linux.die.net/man/1/wsimport-java-1.6.0-openjdk
Best wishes!