Did you read the JAX-WS 2.x spec on this topic?
There are two uses to the WebServiceRef annotation:
1. To define a reference whose type is a generated service class. In this case, the type and value element will both refer to the generated service class type. Moreover, if the reference type can be inferred by the field/method declaration the annotation is applied to, the type and value elements MAY have the default value (Object.class, that is). If the type cannot be inferred, then at least the type element MUST be present with a non-default value.
2. To define a reference whose type is a SEI. In this case, the type element MAY be present with its default value if the type of the reference can be inferred from the annotated field/method declaration, but the value element MUST always be present and refer to a generated service class type (a subtypeof javax.xml.ws.Service).
Regards,
Frits