Hope this doesn't sound stupid, but:
Why not just breed on Black/White 1 and savestate (save after getting the egg, then hatch and check) until you get a poke' with the nature/ moveset that you want, then reset and send the unhatched egg to B/W2 ?
It's what I've been doing, seeing as I have an army of Dittos on the first game (for nature breeding purposes), and it works fine for pokemon you can already catch.
I've also sent over a Snowver egg, but I haven't hatched it yet :p