But my question is how do they do it?

I don't know how they do it. (and true, the 430 doesn't alter the hold
track for wind, though it does for airspeed). There's no reason it
couldn't though - WAAS has nothing to do with it. As long as you know
heading, airspeed, groundspeed, and track, the rest is just math.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.