On reflection, your conclusion is obviously right: playing PD against Honorbot is simply playing Newcomb's Dilemma, so TDT cooperates.
I was misled by the recent realization that TDT doesn't actually work out to "I cooperate iff (you will cooperate iff I cooperate)".
ETA: There is now a third thread, so send new comments there.
Since the first thread has exceeded 500 comments, it seems time for a new one, with Eliezer's just-posted Chapter 33 & 34 to kick things off.
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