Autogen doesn't appear on my phototextures

Hi, I'm working on a photoreal scenery made with Terrabuilder, now the time for Autogen buildings and vegetation has came.

For Autogen I'm working with Microsoft Autogen SDK, but unfortunately just a few random trees and buildings show up in some textures and in other ones nothing happens to be, resulting in a barren desert; not to mention that in the few areas vegetation does appear, that "veg" are actually 3 or 4 trees.

Anyone can help me please with this issue since this area is one of the most populated either by people as well by trees and currently it resembles Gobi or something like that due to this problem.