Output to external screen from iPad

I'm trying to use the TVOutput code (http://www.touchcentric.com/blog/archives/123) to output my iPad app to an externally connected monitor. The code runs fine without any build or runtime errors.

My app is a SplitView with the details view containing a navigation controller. This contains a web view -> Images -> web view.

Now when I test the TV out in the simulator, all I get is the Loading screen of the Images view of the navigation controller, despite it not even being visible yet! Which is weird because the iPad shows the first web view as the correct page.

The images view is done using the Three20 ThumbnailsViewController.

Any ideas what could be going on?

For anyone else's benefit, this was caused by using the TTURLNavigator. When I removed this code, the VGA display code worked.