[exim] bSMTP questions

Hi List, maybe this is a very dumb question, but for some reason i can't
find the answers on the net.

I want to run an bSMTP server for the domainname 'testdomain.com'. After
reading and trying i added this to the exim.conf:

----
acl_smtp_etrn = accept

# BSMTP router
route_append:
driver = manualroute
transport = smtp_appendfile
route_list = testdomeinnaam.nl

# BSMTP transport
smtp_appendfile:
driver = appendfile
directory = /var/bsmtp/${host}
use_bsmtp
user = mail
-----

That seems to work; mail sent to *@testdomain.com is placed in the
/var/bsmtp/ dir.

But now; i want the server to sent the mail to the other (non 24/7 connected
to the internet) server. I read that this is done with the command ETRN. So
i tryed to get that to work too. I have some parts working, but not all:


-----
telnet server2 25
Trying 10.0.0.62...
Connected to server2 (10.0.0.62).
Escape character is '^]'.
220 server2 ESMTP Exim 4.60 Tue, 25 Apr 2006 16:32:16 +0200
HELO server4
250 server2 Hello server4 [10.0.0.62]
ETRN #server4
250 OK
-----

Now i would like that server2 sends the mail to server4. But it doesn't. I
can't figure out what step i have to take now, or what i forget.

My questions:
- How can i get server2 to send the mail to server4 after the ETRN command?
(or on another way?).
- How can i secure this so only server4 can get the mail and not everyone
which type the ETRN command?

Thanks!