double nat with cisco

cisco 805

i need to do something like this

(cisco805) (frame relay) (other box) et0 12.34.56 s0 192.168.161.73 -> 192.168.161.74 -> 192.168.162.230

i need to come to 192.168.162.230 port 2700 with source address of

so in fact i need to telnet to 12.34.56 2700 and get to that

interface Loopback0 ip address 192.168.160.145 255.255.255.248 ! interface Ethernet0 ip address 12.34.56 255.255.255.248 ip nat inside ! interface Serial0 ip address 192.168.161.73 255.255.255.252 ip nat outside encapsulation frame-relay frame-relay interface-dlci 100 frame-relay lmi-type ansi ! ip nat inside source list 20 interface Loopback0 overload ip nat inside source static tcp 12.34.56 2700 192.168.160.145 2700 extendable (double nat?) ip nat inside source static tcp 192.168.160.145 2700 192.168.162.230 2700 extendable (double nat?) no ip http server ip classless ip route 0.0.0.0 0.0.0.0 12.34.55 ip route 192.168.0.0 255.255.0.0 192.168.161.74 ! access-list 1 permit 213.149.32.37 access-list 20 permit 193.203.27.240 0.0.0.7 access-list 30 permit 192.168.160.145 !