Basic ScenegenX help please!!

[Reap]

I just starting with scenegenx. I have it set up correctly I believe and can now place a building and see it i FS9.
However for some reason I cant see runways or aprons.

I have tried with exclude, without exclude and tried altitudes from 0 AGL to 500 AGL (airport alt is 175)
but still I just cant see them?

Any help appreciated Thanks