[Exim] sender_address_relay

Howdy,

    Quick question, I am trying to give
someone the ability to relay through my mail
server from arbitrary hosts. So I have
added the following to my conf and am getting
no joy.

sender_address_relay = @@lsearch*;/etc/relay-users

with the file in question having the following
format.

domain.com    address.1:address.2

I'm guessing this is wrong but would like some
tips.

Also domain.com is in the relay_domains setting.

Thanx in advance guys.

Tom Bell
NCT Computers