smtp ( postfix ) - load balancer --- unable to log source ip

HI

i have set up a pen load balancer on server A with IP 192.168.50.156
listening on 25 to distribute connections to psotfix server B . On
server B i got 2 instances of postfix running on 192.168.50.124 and
192.168.50.125

smtptestserver ~]# netstat -tupln |grep 25
tcp 0 0 192.168.50.125:25 0.0.0.0:* LISTEN 13324/master

tcp 0 0 192.168.50.124:25 0.0.0.0:* LISTEN 13342/master

but the issue is when i receive a mail from a recipient i am not able
to see its source IP address in the logs file ( /var/log/maillog )
... the ip address i am able to see is that from the mailserver itself
 server ( 192.168.50.156 ) . bellow is the log

Nov 28 17:42:24 smtptestserver postfix/smtpd[21943]: connect from
smtpserver25[192.168.50.125]
Nov 28 17:43:14 smtptestserver postfix/smtpd[21943]: C37ED148410:
client=smtpserver25[192.168.50.125]
Nov 28 17:43:19 smtptestserver postfix/cleanup[21947]: C37ED148410:
message-id=<20081128121314.C37ED148410_at_smtpserver25>
Nov 28 17:43:19 smtptestserver postfix/qmgr[13326]: C37ED148410:
from=<agnello_at_yahoo.com>, size=330, nrcpt=1 (queue active)
Nov 28 17:43:20 smtptestserver postfix/smtp[21948]: C37ED148410:
to=<agnello.dsouza_at_gmail.com>, relay=192.168.2.105[192.168.2.105]:25,
delay=21, delays=20/0.04/0.45/0.02, dsn=2.0.0, status=sent (250 2.0.0
Ok: queued as C4F3F6682C6)

Is there any way in pen that it can log/detect the recipient ip address .

Thanks

--
Regards
Agnello D'souza