Cannot stream from time capsule attached disk to Apple TV

Hi,

I have my movies and TV Shows on a disk connected to my Time Capsule. All these videos are present in iTunes and when I want to watch them on my Mac, everything works great. The problem is when I try to watch them from AppleTV (2nd generation). Then, I get the error "There was a problem loading this content, please try again later".

I assume the problem is caused by either one of the two issues:

1) The disk spins down after a while when not in use and/or

2) The disk is not mounted in Finder all the time

When I play the video in iTunes, the disk spins up, is automatically mounted in Finder, and playback starts.

When I play the video in AppleTV, nothing happens and the error occurs.

But when I first play any videos in iTunes, and then play a video on AppleTV, it works.

So, is this a bug in Apple TV / iTunes Home Sharing? Should the video not get mounted automatically as well?

What's the workaround? Force the video to be mounted all the time? How do I do this? There's not such option in Airport Utilities.

Thanks!