Mirror modifier help.

Hi. It seems, that when you use texture uv mirroring in the mirror modifier, it affects all uv channels, is there a way to make it only affect one uv channel. For example, in one uv channel I have specific uv for textures and in the other I have a lightmap uv. It would be nice if the mirror modifier would only affect the channel I want and not mess up the other one.
Any ideas?

I hope there is no need for a blender scene and hope my explanation was clear, sorry if it wasn’t :confused:

Thank you!