[c-nsp] NAT

[Mad Unix]

I have the following situation,a remote office using BRI trying to
connet to our main office PRI In this case the remote office would
like to keep his LAN config as it is without changing the FastEthernet
ip configuration (192.x.x.x) , to resolve this issue I built the FE
with NAT becuase usually I force the remote users to use a specific IP
10.10.x.x?
this what i did in the remote off to make NAT running but its not
working correctly

192.x.x.x  should be NAT to 10.10.x.x

This is the config of the remote office

.........
interface BRI0
 ip address A.A.A.A 255.255.255.0
 ip nat outside
 encapsulation ppp
 dialer idle-timeout 900
 dialer string xxxxxx
 dialer-group 1
 isdn switch-type basic-net3
 ppp authentication pap callin
 ppp pap sent-username .........

!
interface FastEthernet0
 ip address 192.20.20.5 255.255.255.0
 ip nat inside
 speed auto
!
ip nat inside source static 192.20.20.224 10.10.140.100
no ip classless
ip route ...................
no ip http server
!
dialer-list 1 protocol ip permit
...

What could be wrong?