[exim] local and remote smtp server

Hi

I send emails by SMTP.
I now want to use a second server to send emails.

So some emails are sent from the 1st server, some from the 2nd server,
but all is done from the 1st server.

I've a problem when I send emails via server 2 : helo data are correct,
but I have one left problem, on 1st received line.

Line is :
Received: from [IP.SER.VER.1] (helo=mail.mydomain.on.server2) by
name_of_serveur2

=> so, all is good, except IP of server 1

2nd line received is good :
Received : from filter.sfr.fr (localhost [IP.SER.VER.2])

What can I change, to have the right IP in first line received ?

Thanks for your help.