Yes, I've heard about the 3D Max version required. Seems daft not to have upgraded the tools to work with the latest versions but the reality for a small studio like this is time = money!
Have a skim through this thread but there are others about making buildings too.
http://riseofflight.com/Forum/viewto...?f=278&t=32116
Posts by Vander, Ankor and DiFis are the ones to read. These are the guys making the running with 3D objects at the moment. You've got the game haven't you Skoshi?
Have a look at this fantastic 3rd. party map.
http://riseofflight.com/Forum/viewtopic.php?t=34283
Download and use the self-installer.