iPad 'Videos' app

I've hunted through forums but found no clear answer for my issue.

Hi all,
Bought an ATV2 today and am loving it so far.

But I'm having one Airplay issue:
On the iPad, YouTube will Airplay video and audio to my ATV, Photos show up etc, but the default 'Videos' app only sends Audio.

Setup:
- Movies stored on external drive attached to Macbook Pro in study with iTunes & Home Sharing
- iPad & ATV can play all movies themselves
- iPad will only send Airplay Audio of movies to ATV, not video.

Anything I'm missing to get the Airplay Video working too?

Thanks.