Ah, right. The refusal to deal with the other party to the cash transfer could have legal relevance I don't understand, I guess.
Tell you one thing, if I agreed to a buyout clause on my employment contract, I'd have my lawyer try to make sure it wasn't secretly half again as big as it appeared to be if the club decided to be dicks about it. After all, the whole point of the clause is it's something you fall back on when your club are being dicks.
This summer appears to have shown there's a gap in the legal marketplace for people with a real clue about how to get results on football transfers - just look at us and Suarez's pseudo-clause.
Bilbao are an interesting club to have around. I kind of enjoy the whole romance of how they never sell their Basque players, who neverthless all eventually want to leave if they're any good.