Fallback shaders not working in Asset Bundle?

Hi,

I have an asset bundle with a shader (and is fallback shaders) but it seems that the "fallback system" or what you want to call it doesn't work. I noticed the problem because the the shader didn't cast or receive shadows. The shader (Shader Model 3.0) has a fallback to another custom shader (Shader Model 2.0), which fallbacks to the Vertexlit shader, which I have read on the forum should make the shader cast and receive shadows. I also tried to emulate Shader Model 3.0 in the Editor which showed the correct shader, but when I tried to emulate Shader Model 2.0 it became pink as there was no shader on.

Am I doing something wrong? Please help

Thanks, Martin