Calling External Web Service using Windows Authentication (NTLM or Kerberos)

Hello Community,

I’m looking for some guidance on how to communicate with External Web Service that is protected via Windows Authentication.

I’m getting the following error when the PeopleCode below is executed.
Integration Gateway - External System Contact Error (158,10721)
Integration Gateway was not able to contact the external system.  The network location specified may be incorrect, or the site is permanently or temporarily down.

 
The Integration Gateway is working as another Web Service not using Windows Authentication is working.

PeopleCode: 

Local Message &req, &res;
Local SOAPDoc &soap;
Local XmlDoc &xml;
Local boolean &b;
Local integer &i;
Local XmlNode &node, &root;