Is this an enhancement AFCAD only ?
GSX won't work with "partial" AFCAD, which means AFCADs that only enhance on top of the default scenery, but rely on it to have the complete airport. For example, if the original AFCAD included just a runway and some parkings, if the add-on AFCAD only includes taxiways that are designed to integrate the default data, this is not supported by GSX, which expect the one AFCAD in use to be self-contained.