Hi,
OK so we now have an AIM valid Buddy list to which you can add AIM valid names.
appleu3test01, appleu3test02 and appleu3test03 were the first ones Apple set up.
As I posted yesterday there are only two of those On line at present (And the ones ending in @mac.com have not been on line for a while).
Highlighting one of these and using the green video icon will start the Video chat.
AS you are starting to this Test account you should see your Preview in the full sized chat window (i.e. the Video preview fills the Chat window.
Then you will either get a failure notice or the chat will connect.
When it connects your preview shrinks to be the Pic-in-Pic
This is a pic of a chat that is Connecting
The important bit about this pic is the messages about Waiting for Response From...
This actual chat never resolved past this particular message. Is that what you are seeing ?
Or are you seeing something like this Pop up ?
This can be Expanded and Scrolled.
8:36 PM Thursday; August 2, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
 iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images."  No, Seriously