Help wanted with sendmail routing configuration

[Mike Bryan]

My link to the outside world is a UUCP connection with UUNET
(uunet.uu.net).  Currently, I can get mail to UUNET by using addresses
in the UUCP format (i.e., uunet!host!user).  However, I would like to
have mail with an address like "user at host" automatically routed via
uucp through uunet as well, provided we don't know the host locally.
I set up the config file the way I thought it should work, but my mail
gets bounced (locally) with the follow error (sent to user at host.com):

   ----- Transcript of session follows -----
550 uunet.uucp.tcplocal... 550 Host unknown
550 user at host.com... Host unknown

I have not been able to grok enough of the sendmail configuration to
figure this one out.  Does anyone have any suggestions, or a working
configuration file that I can use as an example?

We are running Ultrix 3.0 on our gateway machine, and a mixture of
Ultrix 2.3 and 3.0 on our other machines.  The mailer is sendmail.
I'm using the basic sendmail.cf as supplied with Ultrix 3.0, with
minor changes to have routing to uunet from our gateway, and routing
to our gateway from other machines.

Any help would be greatly appreciated.  Please contact me via the
address listed below.
-- 
Mike Bryan, Applied Computing Devices, 100 N Campus Dr, Terre Haute IN 47802
Phone: 812/232-6051  FAX: 812/231-5280  Home: 812/232-0815
UUCP: uunet!acd4!mjb  ARPA: acd4!mjb at uunet.uu.net
"Did you make mankind after we made you?" --- XTC, "Dear God"