[exim] client_send with an md5 operator?

Hi there,

i want to configure the plain authenticator in exim in this way, that
username and password (that will send by the exim-client) are
automaticly generated by the primary_hostname value. The problem is,
that exim don't understand the md5 operator to build the password.

On exim-client side : client_send =
"^$primary_hostname^${md5:$primary_hostname}"

when i'm trying to send a mail through with this authenticator, the
following output will generated in the log:

"^$primary_hostname^${md5" failed in plain authenticator: "${md5" is not
a known operator (or a } is missing in a variable reference)

When i test this expression with exim -be , the md5 works fine.

Any suggestions?


Thanx a lot.
Mirko