Hi Dragan, I understand this limitation is frustrating, I have come across it myself several times too. As mentioned, triplanar mapping is a special mapping type managed by the renderer that as far as we know cannot be manipulated by RailClone, however, an option for separate U/V/W rotation in the UVWXform operator is something that may be possible from our side. I believe you have already communicated with Carlos about this and I see it's already on our wish list.
Cheers,
Paul