nat with proxy arp question



hello gurus!

i'm currently trying to configure nat using proxy arp on a sunos 5.8 .
this box is running check point fw1 that sits behind my internet router.

i have a server that is connected to the firewall box. i want to translate this server using proxy arp.

settings:
==========================================================

a) fw box "public" interface ip address: 10.1.1.1 (in actual situation uses real public ip).

b) fw box internal interface ip address: 172.16.1.1

c) server interface ip address: 172.16.1.5


i want the server to be translated to the ip 10.1.1.5.

i have gone through these steps in order to set it up

steps:
=========================================================
1) set the fw interface to answer for arp request for 10.1.1.5

arp -s 10.1.1.5 08:00:20:c4:4a:e6 pub

08:00:20:c4:4a:e6 is the fw ethernet address.


2) add routing entries to send traffic to the right destination

route add -host 10.1.1.5 172.16.1.5

==========================================================

there are currently 2 other servers natted this way on the firewall and they work just fine.

firewall rules allow certain tcp connections and icmp to to 10.1.1.5 and 172.16.1.5


am i missing anything? what should i do to make it work...
been trying for the past 4 hours and its already past midnight

thank you so much for any help!

azzuwan,
kuala lumpur, malaysia