message authenticateUserRequest
parts 
parameters
element security:authenticateUser
used by 
Operation authenticateUser in PortType SecurityService
source  
<wsdl:message name="authenticateUserRequest">
  <wsdl:part name="parameters" element="security:authenticateUser"/>
</wsdl:message>

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