Yep, I know about that website - got that bookmarked. And that's the map we got , a readable version that is... :d.
To place buildings, we import the map into a painting program and paint on top of that. We then use the resulting .bmp in gmax (3D modelling program that can export to CFS3) to texture a plane the size of the in-game airfield and then we start placing the building models on top of that. This way you can place them very accurately. The gmax model is exported as a .xml file that can be read by CFS3. Combined with the .bmp in .dds format you get a very fine airfield that is pasted on top of the scenery. Any other way is simply trial and error - a rather time consuming business...
So far we have not found a way to easily work a facility into the landclass files - which obviously would give a better blending result and allows for autogen scenery objects etc. to be used on airfields (pasted facilities flatten or remove autogen objects underneath in CFS3). From this thread I gather that this all is very different for the FS series but the gmax trick for placing models (or something comparable) might be helpful.
Oh, and thanks about the T2 hangar. Knew about that and got that one already modelled (the ACC crew combined has quite a collection of source material for WWII UK airfields). I don't know how big the T2 for this airfield was but a 14 bay version fits the groundtexture. It's big enough for the aircraft stationed anyway.