I imagine that at this time the VPN is terminating in the same burb as the server itself. If so, I can't see how you'd be able to NAT it as both the client and the server are on the same subnet.
If you were to terminate the client VPN on a different burb then this would be possible. You will need to create an access rule granting access to the server (as it is no longer on the same subnet), but the becuase the user is now located on a different burb and it is necessary to use an access rule you can then apply NAT/Redirection/Whatever you'd like.
Hope that helps.
There are two KB articles that go through how to do this:
KB68501: Firewall Enterprise/Sidewinder/Secure Firewall: VPNs with rules using NAT and redirection
KB64313: Firewall Enterprise/Sidewinder/Secure Firewall 7.x: How to create a VPN between two Firewall Enterprise firewalls when the Remote Networks share the same address space
Read through those, they explain exactly how to do this. If you cannot reach the KB I can attach the article to this post also.
thanks for your prompt reply.. I would like to repeat my scenario:
my client is a bank who is havig the Mcafee firewall and they want to have vpn connection with thier customer who has cisco router, so its between firewall and cisco router. Now the bank does not want to expose his local addresses to thier customer rather he wants to NAT 3 ip addresses (Servers) to one ip which is going to be the only ip exposed to their customer and used in vpn too as the local network.. i hope my scenario is more clear now
regarding the diagram i have sent it was just my LAB scenario not the real one.
Thanks in advance