AirHauler communicates with Flight Sim using FSUIPC - if you have installed it, you should see an FSUIPC menu item in the Add-On's menu while flying in Flight Simulator. If not, you can get it from Pete Dowsons pages here: 

You need version 4.53 for FSX, and 3.93 for FS9/2004. You don't need to register it, when the installer finishes choose "enter registration key", and then just cancel.