iChatting with more than two participants

[Jim Soriano]

I've got this problem using iChat (10.2.4)...I can successfully start
iChatting with 1st buddy.  When I go to add a 2nd buddy to the
in-process chat by the following procedure:

"Choose 'Show Chat Participants' from the 'View' menu.  Click the 'Add
(+)' button in the participants list and select people from the Buddy
List to invite to the chat.  If you want to invite someone who is not
in your Buddy List, select Other.  Enter the screen name of the person
to invite."

The 'Add (+)' button remains dimmed and non-selectable even though I
can see the 2nd buddy is online in my main buddy list and I can select
them.  I can start a second separate chat with 2nd buddy, but that's
not what I want...I want a conference!

(Both 1st and 2nd buddies are on various and sundry Windows machines
running AOL IM client...probably Netscape.)

Any ideas?

Regards,

Jim