I follow <[this][1]> tutorial but still overlapping, anything I create overlaps…
Please check my model, made in blender. <[model][2]>
and 1 more model <[model2][3]>
[1]:
[2]: https://drive.google/file/d/0ByK2OJ6Tocq7V3I1NndxWDRuaEk/edit?usp=sharing
[3]: https://drive.google/file/d/0ByK2OJ6Tocq7TTY1WF9CYmtUaDQ/edit?usp=sharing
Are you setting the Lightmap Coordinate Index correctly? You need to tell the editor to use your second UV channel for lightmapping - if you don’t, it defaults to channel 0.
To do this, open your model in the Static Mesh Editor and go into its details. There, find the section “Static Mesh Settings” and expand the options by clicking the small arrow at the bottom of the section. You should see an option there that says “Light Map Coordinate Index” - set this to the UV channel you have your lightmaps on.
Once you’ve done that, save and rebuild. If that doesn’t work, you could try having the editor generate a lightmap channel for you, using “Generate Unique UVs” in the Static Mesh Editor.
Lightmap Coordinate Index is correct (value 1). If I create new its ok, but I want to learn how to do it using blender. Maybe is a bug…
1st model (house):
After that it should work, because I have done it with your model and I dont get any warnings
2nd model (bridge):
Just export it as a fbx or obj and then re-import it into blender. Now create the 2nd uv channel as I show in the video and after that it should work (because the mirror modifier is causing the problem) 
It works, Thank you!