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in this game it wouldn't be a protecting move. But it may be a tactical move to expose a piece to the right spot...
I don't know wether it should be allowed or not (I don't know any 'official rules' to guide me by other than the ones on this site). But if it says the rules are 'the same as in regular chess with some exceptions' and castling is not in the list of exceptions then it should be allowed... or the rules corrected :)