strange sender_rewrite problem

hi together,

for testing I installed TrendMicro Viruswall with configured
smtp-proxy, listening on port 25, postfix reconfigured to listen on
port 10025.
So, I have configured the sender_canonical_maps to rewrite my local
domain (intern.lan) to rewrite the mail-adress to user1@gmx.net etc.
but since installing the proxy it does NOT word without the proxy, that
means, that all addressess are rewrited correctly while useing the
proxy, but no address will be rewrited while using postfix listening on
port 25 with "disabled" smtp-proxy.

Nothing else than the master.cf file (changed the smtp-port to
smtp2-post (10025)) has been changed or modified...

The network-config:
Exchange-Server in LAN: 192.168.1.1 (Domain: intern.lan) forwards
outgoing mails to:
postfix in DMZ: 172.16.14.2 (should rewrite intern.lan to gmx.com etc.)
relayhost in WAN.....


Here comes the config-files:

###############################
sender canonical

user1@intern.lan user1@web.de
user2@intern.lan user2@gmx.net
###############################

sender canonical

user1@web.de user1@intern.lan
user2@gmx.net user2@intern.lan
###############################

main.cf

readme directory = /usr/share/doc/postfix-2.1.5/README FILES
program directory = /usr/libexec/postfix
command directory = /usr/sbin
daemon directory = /usr/libexec/postfix
mailq path = /usr/bin/mailq

virtual maps = hash:/etc/postfix/virtual
transport maps = hash:/etc/postfix/transport
alias maps = hash:/etc/aliases

relayhost = mail.xyz.xyz
recipient canonical maps = hash:/etc/postfix/recipient canonical
sender canonical maps = hash:/etc/postfix/sender canonical

masquerade domains = intern.lan domain.com
masquerade classes = envelope sender, header sender

mydomain = intern.lan
myhostname = server.intern.lan
mydestination = $myhostname, localhost.$mydomain, $mydomain,domain.com
mynetworks = 172.16.14.2/32, 172.16.14.11/32, 192.168.1.1/32,
127.0.0.0/8
myorigin = $mydomain

disable dns lookups = no

relay domains = inter.lan
relay recipient maps = hash:/etc/postfix/relay recipients

smtp helo name = mailserver.domain.com
strict rfc821 envelopes = no

smtpd client restrictions = reject rbl client relays.ordb.org
smtpd recipient restrictions = permit mynetworks, reject unauth
destination, check relay domains

smtpd sasl auth enable = yes
smtp sasl auth enable = yes
smtp sasl security options = noanonymous
broken sasl auth clients = yes
smtp sasl password maps = hash:/etc/postfix/sasl passwd
smtpd use tls = no
smtp use tls = no

mailbox size limit = 0
sample directory = /usr/share/doc/packages/postfix/samples
sendmail path = /usr/sbin/sendmail
html directory = /usr/share/doc/packages/postfix/html
setgid group = postdrop
manpage directory = /usr/share/man
newaliases path = /usr/bin/newaliases
unknown local recipient reject code = 450
##############################

master.cf

smtp2 inet n - n - - smtpd

Would be happy bout some hints or help...

thx in advance so far