Campy 9, 10, and 11 cassettes are interchangeable with 9, 10, 11 speed rear hubs. If I recall correctly, there was a spline pattern change between 8 and 9 speed that causes compatibility issues putting 9, 10, or 11 speed cassettes on an 8 speed hub.

I can't remember, though, if the 8 speed cassette will work on the higher speed hubs.

-j