Adding a USB Drive

Guys, added the patch etc and have also followed someone’s very kind way of editing the menu with SSH. Much appreciated.
What I really need to do is set this aTV up to allow me to load all of my DVD’s to an external drive with my iMac and Mac The Ripper, then unplug from the iMac and plug into Apple TV. Then some how use the menu to see the movies is the higher quality .VOB M the R ripped format and basicly just play it for me the way frontrow will do on my iMac.
Is this possible?
I am a complete novice so appreciate all help that can be given. I have a 40gb ATV with the latest updates and latest version of aTVFlash on it. My iMac is an intel version with Leopard 10.5 on it.
Hope someone can please help me as all I want to do is stream my music with iTunes and watch my movies from the external hard drive
Thanks Guys.