I just listened to the intro to Hissy's program and Biden's name was not mentioned.
Trust me, he does come on. It's actually kind of funny, when Matthews brings him on, he says to him something along the lines of "we're going to have to limit things to the Moussaoui trial today." Biden said something in response along the lines "no problem." It seemed clear that Biden had been booked to tout something else, but he was delighted to be on in any case.