How to Make a Macro Run Automatically?

hey guys

we all know that in order for a ms word/excel macro attack to succeed, the victim has to click "enable content" so that the macro runs....but i wonder if any of you knows a method to make the macro run automatically as soon as the victim opens the document, without the need to click "enable content" (less suspicious) ? unicorn.py says that if you name the macro Auto_Open, it would run automatically...but i tried it, and removed the underscore when using it with ms word (AutoOpen), still the message "Enable macros" pops up. any clues?