message listContainersResponse
parts 
response
element dir:listContainersResponse
used by 
Operation listContainers in PortType DirectoryService
source  
<wsdl:message name="listContainersResponse">
  <wsdl:part name="response" element="dir:listContainersResponse"/>
</wsdl:message>

WSDL documentation generated by XMLSpy WSDL Editor http://www.altova.com/xmlspy