Actually, i may have combined to seperate meetings, I know there is one line of Palpatines though that goes something like 'Master Yoda, do you think it will come to that' refering to war between the seperatists and the republic.
Also, Yoda is like 800+ in the PT, so according to your story that also makes Palpatine 800+. So unless Palps lives as long as Yoda, or can possess newer bodies to keep himself alive (would explain why Yoda doesnt recognize him, though wouldnt he still sense him) then it wouldnt really work.
-Darth Simon.