yeah I dont see a dent either but... If you wanna dent your rubies, grab a dremmel tool (or a normal drill doesnt matter much) and use that as a saw, so just keep drilling and move the drill in a circular form at the place you want your dent to be.
now you've got hole in ur helmet, now get a piece of... well I used aluminium, but I think even cardboard will do, and make a circle out of that material that is bigger then the hole in ur bucket.
now cut out 1/8 or something from the "aluminium"circle, so it looks like a pie with a piece missing, or a pacman... get teh idea?
then, fold the "aluminium" in a way where it gets like one of those japanese hats, liek Raiden's one...from mortal kombat? (I do hope I'm making some sence here)
glue that "hat" to the backside of the hole on ur bucket, now just fill it with bondo or kit and sand it later (if you work properly you dont even need to sand it, just make it a smooth surface with your fingers) tata... worked for me, I'll post pics later. (now for a Fett, this is NOT the most acc way to go but... if yar doing a custom thing... clone, storm, arc...whatever, should do)