i know i need an assymetrical bb but i'm not sure what that means exactly. does that mean that the right side spinle is longer to accommodate the larger crank? am i correct in thinking that a pista bb wouldn't work because it isn't made to work with double chainrings?

what do you think about this:
http://www.lickbike.com/productpage....=%270216-13%27

or this:

http://cgi.ebay.com/Campagnolo-Seale...ts_Accessories