How to make the hidden camo faces work on your character:
Open the "Yourname.ArmA2Profile" (in Documents&Settings/ARMA2 folder) and look almost at the bottom where it looks like this:
Now go through this list of face classnames:
Choose a face you like and add its classname into the face line. Example:
Save the file and dont go mess with faces in the profile section in the game. You wont see your camo face in there if i understood it correct. But it will show in the game.
This works in both SP & MP!
Source: BI forums