I cannot possibly do that, because the default configuration that comes with GSX for that Airbus, doesn't have an ULDCode specified for the front door, and if that code is missing, the Cargo/container loader cannot appear.
I have both front and rear cargo holds set to automatic
This seems to indicate that you have modified the configuration that comes with GSX, because by default, you are supposed to see "BELT", not "AUTO" for the front cargo door.
Use the Reset button of the GSX Airplane configuration page, to restore the configuration to the one that comes with GSX.