Lightmap Texture Camera MipMap Error

Dear support,

I have a problem with my lightmap texture.

I write a shader that multiply my diffuse texture with lightmap (and other mat operation).

See the image in first post of the thread: http://forum.unity3d.com/threads/127238-Lightmap-Texture-Camera-MipMap-Error

As you can see in the first Image, there is a problem with MipMap and Camera Distance.

Infact when I go near to the object, in the second image, the problem disappers.

All the lightmaps are imported as texture (no lightmap). I try to disable "generate mipmap" without fix the problem. So, if I import these as lightmap "texture importing rules", the quality is too much low (I don't know why !!!) and so I'm forced to import them as textures.

Anybody can helps me please?

I need to fix this big problem!!!

Thank you