Can not alter scenery

Hi
Have installed an adon airport with grass runway. Then used
AFCAD to change runway to hard surface and have also added
tower. It all saves in AFCAD but the change does not show in
the simulator. Airport is still the same with grass runway and
without the tower. Looks like AFCAD works on stock airports
but not on adon airports. Any clue how I could make it work
on adons?
many thanks