Rotating a Vector Displacement Map

I have a vector displacement map and want to rotate it dynamically (in UV-space). Below, is an image to outline the current set-up.



The world-space coordinates are rotated by an arbitrary radian value using trigonometry; the output of this is then converted into tiled UV coordinates using modular arithmetic, and panned; these new coordinates then drive an ambient occlusion and vector displacement map.

The problem arises at the vector displacement end of the chain. The radian value needs to transform the vector displacement map, but I can't quite figure out how.

Thanks in advance, guys!