MS Oshkosh scenery, anyone knows how...?

Hi,I wonder if you noticed in the Oshkosh scenery released lately by MS, the photoreal layout of the airport and the surrounding area fades nicely into the default terrain textures unlike other photoreal add ons I saw around and wich are simply a rectangle or box that does not blend with the surrounding like Oshkosh scenery does.Presuming they used Resampler.exe method. So if we use Alpha Chanel to errase the parts we do not want to show we will get water where the Alpha Channel is aplied, is that right? So how did they do to blend it with the default ground textures you think?CheersMichel