Newman's first appearance?

When did Newman first appear? I remeber an early episode with Kramer talking out Jerry's window up to Newman on the roof, but it wasn't Wayne Knight's voice.

     Your memory's pretty good. Newman's name first
surfaces in a very early episode, when he threatens
suicide because he's out of work (just before he hooks
on with the post office, where he's been for 7 years).
And in the original NBC run, Larry David provides
the voice of Newman, who is not seen on screen in
that episode.
     However, you won't get it that way when it replays
in syndication. When the rerun package was put to-
gether, the audio track on that one episode was recut
so that Newman's voice IS now the voice of Wayne
Knight when that episode replays on your local station.
(Several episodes were massaged a little bit when the
rerun package was released...most notably the first
appearance of George's father Frank Costanza. Another
actor played him in the initial NBC telecast...but he was
replaced by Jerry Stiller, and the footage featuring that
other actor was totally reshot for syndication so that
Stiller appears as Frank when that program is rerun.)

When Newman first appeared as an on-screen character a few episodes later, of course, it was Wayne Knight in the role, and it has been ever since.

Bob Smith, afternoons WXXI-AM 1370, Rochester NY