How are the tank gun controls? Is it still the FPS style as in ARMA2 or is it done like in steel beasts? With this I mean, do you control the speed of the turret with the mouse (as you would with a joystick) or does the turret only move when you move the mouse (requiring a mile wide mouse mat to track a moving vehicle)? The tank gunning in the video above looks very jerky so I assume it's still FPS style.
If you map a joystick or game pad to the Aim Up/Down/Left/Right functions in ArmA2, you will get the functionality you require. Try it out, it works well.