ISO6400 access on the 1DM3

Hi,
I've read the manual, but I still can't figure it out.

How do I select ISO6400 (H) on the 1DM3 using the ISO button? I am using Manual mode...

I have CF Fnct 1-3 set registered and enabled to H for High ISO Speed and 100 set for Lowest ISO speed and have Safety Shift disabled.

The highest I can access using the ISO button is 3200. What am I doing wrong here!?

Thanks for any help,

Do you have highlight tone priority on? If you do, you can't access 6400 or 100 and below.

Do you have HTP on? I think that limits you to ISO 3200.
Does the ISO read 32oo instead of 3200? (Zeros are smaller?)

Do you have highlight tone priority (HTP) enabled?

Easy way to tell is if your zeros are small in the ISO display

200 is HTP disabled
2oo is HTP enabled

HTP limits ISO to the 200 - 3200 (or 2oo - 32oo) range.

EDIT: Damn you Nick!

Aha, I do have HTP on...that's something I never would think of.

Thanks everyone!