I know this isn't supported by Orbx but its a temp fix for those who cant wait for the installers come out .I copied the Objectflow.DLL from 11S and changed the name match the one at OG39 and replaced the old OG39.dll and boom all the buildings and trees appeared. I'm going to test at some other airports after I get back from class.

Hope this helps

 

Have you already had the time to test this with other ORBX airports? I'm really keen on using the ORBX airports (especially PAJN) in P3D2 and I don't want to wait until ORBX releases the triple installers (which most likely will still take ages given their update speed...)