Hopefully this is an easy solution.
In your pseudo code you wrote :
objWinHttp.Open "GET", myPBX_IPAddress
This should be a POST and the address you want to post to is : myPBX_IPAddress/xml
The trailing /xml on the server address is how you interact with the server via the XML api. If you don't include the XML you will be interacting with our html interface and thus get the login page.
Also, you still need to login to the XML interface so make sure you pass the proper login information via digest authentication to the XML api.
Here is a write up that details all this found in our documentation wiki:http://developers.digium.com/switchvox/ ... _Interface