WorldAlignedBlend for Normal maps?

[nELsOn]

I’m using WorldAlignedBlend to get a grassy surface at the top of a rock static mesh and that works nicely:

But… is there a way to do the same for the Normal map so my grass normal blends with the rock normal as nicely as the diffuse?
WorldAlignedBlend doesn’t seem to work here and I get this error:

[Tim_Hobson]

I believe there is also a world align blend normal node as well that you can use.