I wanted to bind the AA modes to the boat switch on the Warthog throttle. For anyone else who wants to do the same, here's the relevant code to insert into the Joystick default.lua:
{down = iCommandPlane_HOTAS_BoatSwitchForward, up = iCommandPlane_HOTAS_BoatSwitchCenter, cockpit_device_id = devices.HOTAS, value_down = 1, value_up = 1, name = _('A/A MODE FWD/GUN THREE POSITION'), category = { _('Toggle Switches'), _('HOTAS')}},
{down = iCommandPlane_HOTAS_BoatSwitchAft, up = iCommandPlane_HOTAS_BoatSwitchCenter, cockpit_device_id = devices.HOTAS, value_down = 1, value_up = 1, name = _('A/A MODE AFT/GUN THREE POSITION'), category = { _('Toggle Switches'), _('HOTAS')}},