Port forwarding from behind 2 routers

Hey everyone

i was wondering if anyone can help me out here. i need to port forward from behind 2 routers.

im using a DSL router, a ZTE 831 version 2 and a Linksys WRt160N wireless router.

i need to set up port forwarding, when i do it normally on the ZTE router it works, but i cant seem to set up the wireless router.
also i need the DHCP on my wireless so turning it off is not an option.

if this problem has been discussed before, my apologies and please direct me to the correct thread.

thankyou.

This is my suggestion as well.

WAN NIC (ROUTER 1) LAN NIC 1 <--> WAN NIC (ROUTER 2) LAN NIC 2<--> LAN NIC 3(SERVER IP)

Sorry for the crude diagram. Router 1 you would configure data to forward port X to whatever the WAN NIC is for Router 2. On Router 2, you would forward port X to whatever the LAN NIC is for your server.

ie

Router 1 config: All incomming TCP/UDP for port 21 --> forward to 192.168.1.2 (aka router 2)
Router 2 config: All incomming TCP/UDP for port 21 --> forward to 192.168.1.10 (aka server)

In theory, this should work.