First off, don't use camcreate. Use createvehicle to make new units.
Second, helicopters don't shoot by themselves so you have to create pilots to fly them and do the shooting. Here's an example-
_helo1 = "Mi24" createvehicle getpos logic1
"SoldierEPilot" createunit [getpos logic2, air1, "p1 = this", 1, "CAPTAIN"]
"SoldierEPilot" createunit [getpos logic2, air1, "p2 = this", 1, "LIEUTENANT"]
~1
p1 moveindriver _helo1
p2 moveingunner _helo1
~1
p1 domove getpos logic3
exit
logic1,2, and 3 are gamelogic units you place and name in the editor at the areas you want these things to happen. air1 is the name of a pre-existing group you use to create the pilots for. To make the pre-existing group, put a soldier in the editor, (in this case an east soldier) and give it the group name, air1 = group this; deletevehicle this. The unit won't be in the mission at the start cause you deleted it, but the group name can be used. It's easier than it looks to do all this, just takes a bit of practice.