Yes, I’m able to make normal map in the same uv coords as color map but I want to have more detail. I can achieve it using seamless texture for normal map. In seamless uv I have 300px per face width. In “packed uv” I have only 10px width! So when I read that I can use up to 8 texture coords I’m be happy but no so long 
In blender its simple - set UV, choose which one and done!
If you have 300px normal and only 10 diffuse it will look strange, why not just choosing a texcoord 1 that is more sane ? like 150px for both.
Anyway, jme supports this technically, but noone of the stock shaders does, the blender loader should in theory be able to import them. Take a look at the actual Geometry->Mesh objects if the buffers are present.