How can I correctly rotate a normal map of a given angle in a landscape?

Hi
In my Landscape material, for all my maps (Base Color, Height and Roughness) I lerp between 2 versions of the same texture using a noise as mask.
Version A uses the Landscape Coords straight as they are
Version B uses the same coords but divided by 1.05 and rotated of 28 degrees using a Custom Rotator node.

How can I make this work for the Normal maps too? I read that you can not just rotate them like the other maps. I saw that there is a “Fix Rotate About Axis Normal” material function in UE4.
How can I use this M F or any other method to rotate the normal map so that it works correctly in conjunctions with all the other maps?

Have you tried it, I think you can rotate the normal in the same way.

I tried and it does rotate like all the other maps. My question is, since normals are color coded for orientation, does this rotation ruins the correctness of the normals?
In this video,
link text
at minute 8.00 for a rotation of 90 degrees on all maps a swizzle node is used esclusively after the normal map to compensate for the rotation. I was curious about what was the workflow for a rotation that was not 90 degrees.

As far as I know, it’s ok as long as you’re doing the same things to the normal as you do to the albedo.

Watching the vid, I think he already has rotated the normal. I don’t know if he needs to do that twice…

Gotta say also, this:

is a better method in my opinion. You don't have to mess with any tiling, the shading does the whole thing.