how i can use uv channel 2 in 3dsmax to bake lightingmap in unity3d ?

i create channel 2 in 3dsmax but when i import fbx in untiy3d and bake map uv auto rearranged( now uv not same in 3dsmax i created)

i not check (Generate lightingmap uv) in fbx

now how i can use uv channel 2 i created in 3dsmax to bake lightingmap in unity3d ?