Tree Soft Occlusion Bark lighting problem

Hello, I'm having issues with the Nature/Tree Soft Occlusion Bark shader having really bad lighting. When I shine a spotlight close to it the whole thing lights up, even when the spotlight isn't shining on it like in [this picture][1] (Not my picture, but it's exactly the same problem). I've somewhat found a solution to this by using a normal Diffuse shader on the bark, but doing this causes other issues: 1) Trees sometimes glow white when billboarding. 2) The geometry seems to be shifted when I place the trees on the terrain shown [here][2]. I'm just wondering there is a better solution to this that doesn't cause these problems? [1]: http://i46.tinypic.com/sl76mq.png [2]: http://i.imgur.com/Ibc1HLY.jpg