For your example, you are right, the content of interest does not appear in the HTML source of the page. This is because the webpage is being updated with AJAX using this library (I think).

Here is my (simplified) view of the browser:

Code From -> (Java)Script -> Internal -> Renderer
Internet     Engine          Document
[download]

What you are seeing with the view-source is the code from the internet. But what you need to be looking at is the internal document output by the script engine.

I know you can get this using the JavaScript plugin for WWW::Mechanize. I am not familiar with Win32::IEAutomation, but it would seem to me that the Content() method should return the internal document.