Misdirection + Duels

I attack someone's provinces and as my first action in the battle I play First and Final Strike, he plays Misdirection to target another one of my personalities instead. Is that legal? I didn't think you could duel your own personalities so I would think that you can't play Misdirection that way. Any help would be great thanks.

Battle: Target one of your unbowed Personalities: He challenges a target Personality opposing him. Destroy the loser. The winner’s controller gains 3 Honor if the winner had less Chi than the loser before the fi rst opportunity to focus or strike.

Political Gozoku Reaction: Before another player would choose targets for one of his actions’ effects during a battle, target one of your Courtier or Gozoku Personalities: You choose the targets instead.

If you play First and Final Strike and your opponent wants to react with Misdirection, he must do so after you target your performing unbowed Personality and before you choose the second required target. Then Misdirection's Reaction would allow your opponent to choose the Personality who will be challenged. Personalities you control are never opposing your performing Personality, so they are never legal second targets for First and Final Strike, so your opponent can never choose any of them as its second required target: he must choose a Personality opposing your performing Personality (First and Final Strike's text).

I am confused by http://www.alderac.com/forum/viewtopic.php?f=59&t=74656. Why can you not change the target personality that performs the duel?