How do I know if my ext HD is my primary storage

I think that I have followed the directions from the wiki correctly, but how do I know if the USB external harddrive is the primary storage for syncing with itunes?

Thanks

The only way I know of is if iTunes sees the expanded storage in the size bar when you click on your AppleTV.

I see, I must have done something wrong. The appletv stills show up as ~32gb, however, I am able to transfer files to it (ext hd) using winscp. The “my Book” shows up in the movies folder, with (what looks like) a little shortcut symbol on the icon. Does this sound like a normal condition? Do you think I’m close?

Thanks for the help.