No, with the AH II update I use the HTC default "grass field" with grassy looking runaway. We cannot do any custom fields with this Terrain Editor version, but as HT has promised the "Customize Friendly" editor is coming in the near future. I am really waiting for it!
In the earlier FinRus I made the "Backwoods Airfield" using one almost invisible VDEPOT object (Vehicle field) as a runaway and situating trees, acks, revitments etc. around it. You could make objects invisible painting the "alpha" -filter (VDEPOT_a) with gray scales from white to black.
I draw straight to this VDEPOT object the sand/grass -looking areas, and the texture (for ex. "Grass" or "Forest") under it was also visible, because the VDEPOT was partly transparent. It was really a small airfield like they were on those days in Finland.
Better looking open area fields were in the Kurland map, where I placed four totally invisible VDEPOT's as runaways and over them one big LAKE1 object: I draw/skinned the snowy runaways with Photo Shop to this object.
This is it:
