Tree Soft Occlusion shader makes trees invisible in editor

Hi all. I imported a tree model from blender as .fbx to 'Ambient-Occlusion' folder in the 'Assets' root as Unity documentation suggests. 2 materials were successfully generated and I assigned 'Nature/Tree Soft Occlusion Bark' and 'Nature/Tree Soft Occlusion Leaves' shaders and appropriate textures to them. Unfortunately this makes my .fbx model invisible either when I place it directly to the scene and when I use it as tree in Unity terrain trees system. When I running the game mode trees placed with Unity terrain trees system becomes visible But fbx which were directly placed still seems invisible. I noticed strange things when trying to play with built in Unity tree. It also has 'Nature/Tree Soft Occlusion' shaders but they seems not the same shaders as I can select in shaders menu! As you can see checkbox of 'Nature/Tree Soft Occlusion Leaves' shader not checked. If I check it the appropriate material of palm tree also becomes invisible exactly as I described above for tree model imported from Blender. As additional information I can say that project was originally created in Unity 4. So problem might occur when importing to Unity 5. What I'm doing wrong and how can I fix this? Thanks in advance.