Are you saying you remeber it first hand or are you saying you remember hearing about it?
I tried to check out this debate with Alan Keyes. First off there definitely would be a recording. I believe my conclusion was that the rumor was false. Alan Keyes has never mentioned it and he has been asked I am sure.
That would have been something.
There have been two or three people on FR who heard the debate and heard the exchange. One of them corresponded with me on a thread not too long ago. If I remember tomorrow I’ll try to dig it up.