Richard, I read your mail of Jul 28 11:55 CDT which had a question
addressed to me.  I think that Eric's mail of 18:14 BST answers it.
The Newsgroup header that is being created just isn't designed to be
used for mail.  It needs to be a newsgroup name, not an address.
 
As an aside, I think that an earlier piece of mail from Eric today
explains why we need an address;  it turns out that given just a
Sender header, we cannot reasonably perform the Listserv list ->
Usenet newsgroup mapping.  It would require each netnews gateway to
have a table mapping listname@address to newsgroup.  The table would
need to be updated on all netnews gateways whenever a list was added
or deleted from any peer.  Instead, we will distribute this table by
giving control of each (listserv list-> netnews group) to the
individual listserv list owners.