[Exim] exim authorizing at a smarthost

hi exim users,

my exim 3.36 is a lan mailserver, it must authorizing to our
main mailserver. how may it configure to obtain that?
it must are a smtp auth login or cram-md5 (md5 are better;))

so the exim behavior must are like a client that send a mail
to the mailserver. the main mailserver is configured
as smarthost for our exim lanserver.

thanks!
Tobias