>If you are the list owner or the postmaster, I think Listserv treats
>you as a special case.

Nope.  Something else is wrong.  Owners can only post if they are
also editors or subscribers.  Being a list owner does not give you
any special privilege to post.

FWIW, Reply-To= only tells LISTSERV what to place in the Reply-To:
field.  Whether or not your mail software respects the Reply-To: field
in mail you receive is a completely different story.  This can lead
to the incorrect impression that LISTSERV is not putting the right
data in the Reply-To: field when LISTSERV is actually doing what it
is told and it is the remote client that is doing the wrong thing.
As Pete has already noted, it is not relevant with regard to poorly-
implemented auto-responders and/or OOO programs that aren't designed
to look for the Reply-To: (or even the RFC821 MAIL FROM:) field and
respond non-compliantly to the RFC822 From: line.

Nathan