They used an analog joystick with a gun on it... and instead of lean left/right, its twist left/right.
You can get them on ebay pretty regularly.. I got 2 for 20bucks or so..
Then... 1ups starwars hack (about 10 bucks each)...
But I don't know of any other solution.
You can kinda get an actlabs to work... but you have to add the second button to be a button 1 also... so you press the main fire button to move the gun... and the second to continue the machine gun... but it really isn't the same.