Not that it means anything, but the Ard Boyz rep (Brendan Bell) sent the finalists an email about this topic.
Make what you will of it.
There have been a number of questions regarding Demonhunters and Witchhunters and allies for the 2010 40K Ard Boyz Finals.
The Finals will use the printed rules that were used in the first two rounds; you will be able to use allies.
I only wonder that if it was an incomplete codex... why would he have worded the answer like that?
It's rather strange.
Anyways, as always, emails can't be trusted, but this one doesn't seem to give any definite answers so perhaps it was worth posting for you all.