Turret weapons

Okay, problem is that I've given several of the vehicles turrets a second weapon. However, human players can't fire them with any button, even though AIs can. What am I doing wrong.

Here's the script for the tiebomber bombardier
And here's the Imperial Tank Turret

Vehicles can only have one weapon per unit slot. There's no keymap set up that includes both a secondary fire and a position swap button.