There were a couple of points about DX10 White Caps that I thought worth mentioning.
When using DX10 it is best to avoid water textures that contain a wave pattern. An example of this is the REX Bare Floor texture.
FSX in DX10 mode aligns the white cap waves with the wind. It is unaware of the contents of the water texture so the white cap breaking waves will usually therefore not align with the waves inside the texture which looks plain wrong.
Secondly the white caps are really just flashes of light superimposed on the texture. When looking at a sea plane floating in the water you will see white flashes pass along the water. To me this looks wrong, I may see if the white caps could be excluded in the immediate vicinity of the plane.
Now here are some screenshots of night lighting – I suspect that these may all look the same on the web, but here goes.