Can I use the router for DHCP with RIS?

I’m using W2k Server w/AD. When using DHCP on the server RIS worked fine. I installed a Netgear FVS318 Firewall/router and set it to provide DHCP and turned off DHCP on the server. Now when I try to use RIS, I get a message at the client computer that the DHCP server cannot be found. How can I make this work?
If I have to use the server for DHCP, how do I use the firewall? It’s my understanding that the firewall provides it’s protection principally by use of NAT which implies DHCP.