[exim] Authentication and Verizon

I have a basic Verizon account with eight email addresses. I want
to have all outbound mail go to a local exim smarthost to
outgoing.verizon.net as its smarthost. I don't know how to set up
authentication.

At present, only the user first found in passwd.client is able to
send mail:

outgoing.verizon.net:yellow:yellowpasswd
outgoing.verizon.net:red:redpasswd

I understand that I am lsearching this file by the host name, and
so I am only finding the first line. Should I be searching by
host and user? And how? Or something else?

This is the log for a failed mail:

O2007-03-06 16:15:51 1HOh0h-0005uD-Dn <= red@??? H=shackles
(localhost.localdomain) [172.16.2.100] U=red P=smtp S=626
id=20070306161551.4f8c86d8.red@???
2007-03-06 16:15:52 1HOh0h-0005uD-Dn ** user@??? R=smarthost
T=remote_smtp_smarthost: SMTP error from remote mailer after MAIL
FROM:<red@???> SIZE=1667: host outgoing.verizon.net
[206.46.232.12]: 550 5.7.1 Authentication is required to send mail as
<red@???>
2007-03-06 16:15:52 1HOh0i-0005uG-6i <= <> R=1HOh0h-0005uD-Dn U=Debian-exim
P=local S=1621
2007-03-06 16:15:52 1HOh0h-0005uD-Dn Completed

Thanks.

rir