Sendmail Problem Stable 4.0

[Tortise at Paradise]

Dear All

I have a FreeBSD 4.0 stable box with Sendmail, ipfilter and apache working on it.
I am changing my setup here to use the box principally as a firewall and pass or relay mail through it to an SMTP server behind the firewall.
The SMTP mails are rejected.
The SMTP gets thru when the firewall box is removed from in between.
I have created and edited sendmail.cw to include the domains I want relayed.
I have edited the NAT config file:

map ed0 192.168.0.0/24 -> 0.0.0.0/32 portmap tcp/udp 40000:65000
map ed0 192.168.0.0/24 -> 0.0.0.0/32
#DH added for mail 2003-11-16
rdr ed0 192.168.0.0/24 port 25 -> 192.168.0.30 port 25
#DH added for WWW server 2003-11-16
#rdr ed0 192.168.0.0/24 port 80 -> 192.168.0.30 port 80

The smtp server is on 192.168.0.30.
The internet side is 192.168.1.x

I think something else needs to be done to persuade sendmail to relay the e-mails, but what?

Any assistance would be greatly appreciated.

Kind regards,
David Hingston