service-ref-name

only one 

Specifies the web service reference name relative to java:comp/env.

port-info

zero or more 

Specifies information for a port within a web service reference. 

call-property

zero or more 

Specifies JAX-RPC property values that can be set on a javax.xml.rpc.Call object before it is returned to the web service client.

wsdl-override

zero or one 

Specifies a valid URL pointing to a final WSDL document. 

service-impl-class

zero or one 

Specifies the name of the generated service implementation class. 

service-qname

zero or one 

Specifies the WSDL service element that is being referenced.