I am assuming it will work the same, but we will have to wait till it comes out.
Actually let me clarify - if you want to transfer your old black and white pokes to black and white 2, then you can pokesav pokes to BW2 and trade to BW old (could even be the same poke 300 times)
If you jsut want pokes in BW2 and don't care if they are the ones already in BW old, you can just pokesav for new pokes in BW2
Assuming pokesav works the same for BW2, yes you can customize ivs and evs, original trainer name (and ID number if you download one to pokecheck and find out what it is.