HDR Video - Are there settings needed to allow me to focus properly

[freakygeez]

Hi,

I'm new to HDR in video so please forgive if I'm missing something, I have a Canon 600D.

When I switch to HDR I want the screen to display the lowest ISO when I'm recording and not alternate between the two every few seconds as this makes critical focus impossible but when I'm framing up I still want it to alternate.
Am I missing a button somewhere?