Device cisco 2911 router configuration support is required please.

I have exchange server 2010 configured and working without any errors the problem is in cisco router configuration when exchange server sends emails out the receives WAN IP not the public ip. I have configured RDNS lookups with our MX record IP addesses that match the FQDN but all our emails are rejected because it does not match with the public ip. Receiving mails problem is not an problem all mails are coming through. i am sure i am missing something on the router configuration that does not sends the public ip, can any one help me to solve this issue.

Note; I've got 1 WAN IP & 8 Public IP from ISP . Find below the running configuration.

Building configuration...

Current configuration : 2734 bytes
!
! Last configuration change at 06:32:13 UTC Tue Apr 3 2012
! NVRAM config last updated at 06:32:14 UTC Tue Apr 3 2012
! NVRAM config last updated at 06:32:14 UTC Tue Apr 3 2012
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
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hostname BSBG-LL
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boot-start-marker
boot-end-marker
!
!
enable secret 5 $x$xHrxxxxx5ox0
enable password 7 xx23xx5FxxE1xx044
!
no aaa new-model
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no ipv6 cef
ip source-route
ip cef    
!
!
!
!
!
ip flow-cache timeout active 1
ip domain name yourdomain.com
ip name-server 213.42.20.20
ip name-server 195.229.241.222
multilink bundle-name authenticated
!
!
crypto pki token default removal timeout 0
!
!
license udi pid CISCO2911/K9 
!
!
username bsbg
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!
!
!
!         
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interface Embedded-Service-Engine0/0
 no ip address
 shutdown
!
interface GigabitEthernet0/0
 ip address 192.168.0.9 255.255.255.0
 ip flow ingress
 ip nat inside
 ip virtual-reassembly in
 duplex auto
 speed 100
 no cdp enable
!
interface GigabitEthernet0/1
 ip address 213.42.xx.x2 255.255.255.252
 ip nat outside
 ip virtual-reassembly in
 duplex auto
 speed auto
 no cdp enable
!
interface GigabitEthernet0/2
 no ip address
 shutdown
 duplex auto
 speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat inside source list 120 interface GigabitEthernet0/1 overload
ip nat inside source static tcp 192.168.0.4 25 94.56.89.100 25 extendable
ip nat inside source static tcp 192.168.0.4 53 94.56.89.100 53 extendable
ip nat inside source static udp 192.168.0.4 53 94.56.89.100 53 extendable
ip nat inside source static tcp 192.168.0.4 110 94.56.89.100 110 extendable
ip nat inside source static tcp 192.168.0.4 443 94.56.89.100 443 extendable
ip nat inside source static tcp 192.168.0.4 587 94.56.89.100 587 extendable
ip nat inside source static tcp 192.168.0.4 995 94.56.89.100 995 extendable
ip nat inside source static tcp 192.168.0.4 3389 94.56.89.100 3389 extendable
ip nat inside source static tcp 192.168.0.4 443 94.56.89.101 443 extendable
ip nat inside source static tcp 192.168.0.12 80 94.56.89.102 80 extendable
ip nat inside source static tcp 192.168.0.12 443 94.56.89.102 443 extendable
ip nat inside source static tcp 192.168.0.12 3389 94.56.89.102 3389 extendable
ip route 0.0.0.0 0.0.0.0 213.42.69.41
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access-list 120 permit ip 192.168.0.0 0.0.0.255 any
!
!
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control-plane
!
!
!
line con 0
 exec-timeout 5 0
line aux 0
line 2
 no activation-character
 no exec
 transport preferred none
 transport input all
 transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
 stopbits 1
line vty 0 4
 password 7 xx64xxD530D26086Dxx
 login
 transport input all
!
scheduler allocate 20000 1000
end