Playing ISO Format Videos off External Hardrive

 bought a copy of the Firecore software specifically for the original APPLE TV (Silver model).  I loaded the firmware and all of the freeware applications seem to be working.  My problem is this.  I formatted a fast 2T drive using Mac OS and dragged on 280 movies to the hard drive.  When I plug it into the USB on the AppleTV, it sees the drive and can read the titles but I cannot play them.


I copied all of these movie disks using the ISO format.  I can play these disks on that 2T hard drive by attaching this USB drive to my MacBook  But I cannot play them with the AppleTV (only see the titles).  Any ideas??