Skulls in Halo 3?

[Scott]

This is a question only for those who have *achieved* the halo 3 skulls, and are just simply in the quest for them.
Please tell me if you must 1.) find the skull and finish the mission while HOLDING the skull; find the skull and make a kill with it; or just find the skull. and 2.) if you must find the skull on legendary or heroic in order to make it work.
I have found the Grunt Birthday Party Skull, however was on normal, and only made one kill with it before leaving it. However when I made a headshot on that mission on a grunt, no confetti... Not sure why.
Now when I tried to find the skull on legendary and heroic, its a no show. So what level do I have to find the skull to make it work, how far must I go with it, and will collecting all of them get me that neat mask?
Thanks in advance for your time and knowledge. It's much appreciated

 

[Philip]

skulls are achieved straight away. i just pressed the save and quit after finding one. and you need togo campaign then press X i think to change the settings *(cant remember what button) and put the skull in place. best to play in normal. some skulls are hard to get