According to the Campag PDF from
here, you want 279mm spokes for the driveside.
There are all sorts of codes depending on how many in a pack, but it is either Kit-14SC or WH-006SCC.
Your LBS will be able to supply the exact spokes if you can wait a few days, but they did my rear Vento with a decent spoke which was slightly thicker in a couple of hours.
If you want to buy spoke yourself, contact
Italian Cycle Products.