Not sure it's empty, but I agree that Paul Vallely isn't worried about it.
Interesting case scenario. I don't recall any defamation cases where the allegation is based on a conversation between only the plaintiff and defendant, with no other witnesses. What would really be a hoot would having Wilson try to obtain a court order against Vallely, enjoining him against speaking out further.
Grampa Dave and I both heard Vallely say his (Vallely's) wife was in the green room at the time.
Also one of the links on this thread (forget which one) has info to the effect that General McInerney (also a consultant to Fox News) heard the same bragging from Wilson. I would assume that if that's true, it wasn't necessarily on the same date, however.