You need a 10speed campag freehub as the campag freehub fittment is the same for 10/11 spd cassettes. Or you can get a 11sp cassette that fits on 10spd free hub, they exist but aren't cheap.
Neither option is cheap.
I'd just rebuilt wheel with new 11spd hub.
If the hub is not the 40t engagement you can't put the 11spd Shimano free hub onto it.
I have just had to get new wheel built with the new hope hub to run an 11spd group set.
@dancing james started
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You need a 10speed campag freehub as the campag freehub fittment is the same for 10/11 spd cassettes.
Or you can get a 11sp cassette that fits on 10spd free hub, they exist but aren't cheap.
Neither option is cheap.
I'd just rebuilt wheel with new 11spd hub.