Just found this on the Microsoft Halo2Vista forums. It was put up by one of the admins there.
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I. <SPAN>Create silver accounts on www.xbox.com (http://www.xbox.com/) for each server instance that you plan to create. Make sure you remember their email addresses and passwords.
Whoa not sure what happened there let me link to the post.
http://forums.haloonwindowsvista.com/forums/thread/1267.aspx