As mentioned above, Campy cables have smaller end fittings than Shimano compatible ones. This is particularly true for shift cables and to a lesser extent for brake cables so be sure the cables are Campy compatible if not genuine Campy. Jagwire cables are great and there are "universal" shift cables with a fitting at each end, one Shimano, one Campy, and you cut off the unneeded one.

I've used both genuine Campy shift cables and Jagwire's compatible ones and the bike never knew the difference but my credit card did.