Newbie has some questions on ISO

[jaffaro]

As you guessed by the title, im a full new user on Magic Lantern and most of the features are weird to me, but hey! i wanna learn how to use it!
Anyway, i read about the ISO options that ML offers, and i read about bumping your ISO to 50, and making your shutter fast with 1/8000, but what i don't understand is why when i try to use those features on P or M (By the way, im using a T3i with the last Nightly Build) i can't put the shutter speed over 4000 or set the iso less than 100.
Can anyone help? Even if i try to use those settings on the movie mode for taking photo, the camera doesn't take the picture with those settings.

Sorry for the bad use of english.