ML auto ISO can't be working, it needs prop change.
I thought it worked. Here is how i tested it:
In movie mode/AV, set the Canon ISO to 100. In ML menu set Exp override to ON. Turn the ML ISO to 100. Turn the ML auto ISO on: Now the iso rises in steps up to 1600, but the AV Shutter and Aperture sustains unchanged. The LV is now brighter, and if you shoot a movie, that will also be that bright too.
BUT the ISO only rises. Not even when i point the lens directly to bright light it goes down...
Now i see a short message on the screen when i turn on the camera with theese settings: "!!! Auto Exposure !!! Set Movie Exposure -> Manual in Canon Menu". So I suppose Canon exposure is working in the background... 
Glad to see more testers here, blade!

Good to see that you double check my testings - maybe other combination of settings can bring other results. I'm also a bit confused of what props does...
