pinging Intranet using Active Directory credentials

[Mark E. Powell]

I can see the corporate intranet through browsers and other tools.  However, when I use 'load URL' type calls within Rev to the intranet location I get HTTP Error 401.1

Unauthorized: Access is denied due to invalid credentials.

I am sure this is because the corporate image is set up to read Active Directory credentials transparently.  

How do I do the same from a Rev standalone?  Is there standard syntax for passing these parameters?  

TIA for any life raft you have to spare.

Mark