[exim] unroutable address root@localhost

What is the nicest way to make exim 4.50 to route these messages into a
maibox assigned for root in /etc/alias file?

2005-03-06 22:49:14 1D82ga-00067Q-Qg <= root@localhost H=localhost
(garfield.tee-en.net) [127.0.0.1] P=smtp S=810
2005-03-06 22:49:14 1D82ga-00067Q-Qg ** root@localhost: Unrouteable address

The messages are sent by some local service with tcp/ip to root@localhost,
obviously with no from information.

I guess my acl already accepts messages from 127.0.0.1, so the problem would
be to handle "localhost" in a proper way?

--
TiN