As far as I know there isn't really a way, unless you alter your eq.ini files (someone else will have better info on this).
I would suggest finding a helmet that has a no-show graphic. I also can't stand any helmet of any type, I like all my char's handsome faces to be viewable.
Allakazham is a great resource for this. Look at the
Othmir Cap for example, it has a 'leather' looking icon, but the Appearance tab on the left is cloth (cloth = no helm graphic).