I have just heard that President Klaus is now being accused that it is too late for him to demand the exemption from the Charter of Fundamental Rights and that he should have done it earlier. The difficulty is that “earlier” the Lisbon Treaty was dead because it was rejected in Ireland, as you know, and unanimity was and is required for its ratification and implementation, if the EU follows its own rules.
That is why President Klaus came up with this demand after the second Irish referendum. He is not demanding anything special, but “only” a legal guarantee which the EU has already granted to two other EU member states. And he requires this guarantee to be legally binding.
(I am currently writing this up in The European Journal).