From IS 7.1 WS developer’s guide, page 14:
Define one or more “aliases” to be used with dynamic endpoint addressing for both
provider and consumer Web services. For a provider Web service descriptor, the alias
is used to populate the endpoint address of the Web service when generating the
WSDL. For a consumer Web service descriptor, the alias is used at runtime, when a
Web service connector is invoked, to determine the actual endpoint address of the
web service and/or to supply user credentials to be used with the request.
this is the case only for 7.0 or later.
#webMethods#API-Management#soa