I stumbled on the solution to my question. To stop the second
authentication, I have toprovide the fully qualified URL of the file.
For example if I used
http://aemserver:8080/soap/services/WSDL/manualTest?wsdl&lc_version=11.0.0,I
will get a prompt. When I use
http://aemserver.myunit.mydepar.myorg:8080/soap/services/WSDL/manualTest?wsdl&lc_version=11.0.0,I
do not get the second prompt.