[Serusers] How to rewrite source IP -- SIP packet forwarding.

I'm using nathelper with SER. Here's a quickie diagram of my setup: [SIP ATA] <-------------> [SER] <------------------> [Asterisk] 10.0.201.5 eth1 - 10.0.201.7 eth0 - <public_ip1> eth0 - <public_ip0> I'm using the basic nathelper example configuration, except for one modification. I removed the call to t_relay and replaced it with: t_relay_to("<public_ip1>", "5060"); Basically I want a SIP packet to come in to eth1 on SER server, get rewritten as needed by nathelper, then get sent out to public_ip1 on my Asterisk PBX. This appears to be working except a tcpdump on eth0 on SER shows: 14:39:08.654908 IP 10.0.201.7.5060 > <public_ip1>.5060: UDP, length 629 Obviously the packets will never get back with that source IP address. What command should I be looking at to rewrite this IP so it shows up as <public_ip0> automatically? I'm trying to get SIP ATA's to REGISTER on my Asterisk box but proxy through SER ... (and eventually make use of the rtp proxy). Can post more info if requested, I am new to SER. :-) -- Ray Van Dolson Linux/Unix Systems Administrator Digital Path, Inc.