Three NIC problem

I have a problem. I am installing a Storm box. It has to have three NICs.
This is because two if the NICs will be used as the gateways for our
internal workstations. At the current time some of our workstations use one
gateway, a T1, and the others use an other gateway, an ISDN line. This new
firewall has to have NICs for each of these gateways. This way we can remove
these firewalls without having to reconfigure all the workstations. The
third NIC will be used to send data out to our Cisco router which we will
use to do the routing for all our network. The idea is to use the current
gateway IP of 192.168.1.204 (T1) and 192.168.1.79 (ISDN). The third NIC will
be given an IP of 10.0.1.1 that will be used to pass all traffic to the
router.

Question:

How do I get the Storm box to route both of the functioning gateway IPs out
the third NIC to the router? I thought I had the routing table and the NICs
configured right but I can not get anything to pass out the third NIC.

Thank You,

David Demland
Qa/Process Manager
CADTEL Systems, Inc.
11201 N. Tatum Ste. 200
Phoenix, AZ 85028
(602) 648-6054
Fax: (602) 648-6054
ddemland@cadtel.com