I'd say if a 200,000-kilo plane is in the air, and at less than 60 kts, it is stalled, regardless of whether the AoA vanes are trustworthy at that speed.
The Stall warning logic should be "if the plane is not on its wheels, and the AoA vanes indicate a stall, then the warning sounds. It ALSO sounds if the plane is not on its wheels and the AoA vanes have reached their maximum reliable point (even if no longer trustworthy)."
I'll concede that an A330 in the air at 60 kts is improbable - but the improbable is what warning systems are intended for.
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RE: the reported quote from the Captain "We're in a stall, REDUCE power and pitch." I take it that has to do with the A330's low under-wing engines? A high power setting (or rapid power increase) would cause more pitch-up, making it harder to lower the nose and break the stall? We've seen that noted in the case of 737 stalls or go-around incidents.
Usually, stall recovery involves INCREASED power.