Wind shader problem: Does Blender only export, or UDK only import vertex colors as 0 or 1?

I have a wind shader that is working just fine when I export my meshes from Blender with the default all-white vertex colors. I multiply the WorldPositionOffset by the vertex color so that white vertices have 100% movement and black vertices don’t move at all. That works fine. But the gray vertices all seem to have 100% movement instead of the expect gradient.

Have any of you ever noticed a similar problem? Does Blender only export vertex colors as 0 or 1? Does UDK only import vertex colors as 0 or 1? How do you import your vertex colors?

Edit… OK, it seems like the issue may be something else. I can change all sorts of things in Blender, and export the fbx file, and have the changes show up in UDK. But I cannot change the vertex colors. I just painted all of the vertices white, exported, imported, and the same vertices are anchored. So I guess I need to find out how to force Blender to overwrite the vertex colors or force UDK to refresh them.

I think I can get the vertex colors to refresh if I export at a different scale, import into UDK, export again at the desired scale, and import into UDK again. Something about that workflow causes the vertex colors to get refreshed.

Im not sure,but i think ive heard that there were some minor problems with the fbx blender plug in long ago.I dont know if you coud try a older or newer updated fbx.