I have just asked ffg for an official answer and will post the response as soon as I get it.
Unit leader and Command Section
Zach at ffg has given an official answer to this:
The entire Command Section must be eliminated before a player must nominate a temporary Command Section. If a Command Section loses its Unit Leader, a new one is promoted from amongst its remaining miniatures during its next activation.
I hope this has answered your question. Happy Gaming!
