Yes, I do have MCM installed. And I did check to see that the feature was enabled. I tried un-checking and checking, restarting the game, un-equipping the helmet and re-equipping it, but it never worked, not even once. Maybe it's because I was trying it on the wrong helmet? Does the mod work on Riot Helmets? Because that's what I had been using. Do you have the dlc patches installed? If I'm not mistaken riot helmets came with a DLC, so you'll need the appropriate patches. Do your vanilla helmets work though? Oh and here's the link for the patches, they're on a separate nexus page so you might have missed them http://newvegas.nexusmods.com/mods/42363/