"I tried to remap V2 to take V3 textures but it does not work."

And it shouldn't. We never intended for V2 to take V3 maps... that is not what the .uvs files are provided for.

"Remapping the other way round - V3 to take V2 textures works fine..."

Which is our intention; they are for remapping V3 to accept V2 textures. Both uvs files have V2 type UVs with V3 facet structure. The one with "mat" in the name includes material assignment as well.

-Rob