the wave deformer, along with any other deform modifier in max will not be exported as .x. Panda doesn't do it, DirectX doesn't do it, no real time engine will do it. The only place you'll see it work, is in max.
DX needs bones to deform verts.
and to save you some time, you won't be able to put a bone structure onto the plane, and then apply the modifier to the bones, as that won't work either. The only thing you can do for this, is to code the waves yourself using DBP's new vert manipulation commands
I don't have a sig, live with it.