How to rotate a custom tree ?

Hello!

After creating and painting a custom tree to my terrain, model is laying on its side. How could I rotate it ?

Same imported model works fine when used as a standard GameObject, then it needs to have -90 rotation on it's X-axis to stand up. I've tried using different rotations and updating tree prototypes - no rotation is affected to trees on terrain. Model has two submeshes and nature shaders applied.

Tree model is imported from 3dsmax 2010 via fbx-format (latest exporter 2011.3 installed). All FBX-based models seem to have 270 (-90) degrees of rotation on X-axis initially. Changing the setting Z-up or Y-up from fbx exporter settings does not effect rotation in Unity at all.