Alcatel SpeedTouch 510 in routed IP mode?

Can anyone help me with reconfiguring our SpeedTouch from NAT/PAT mode to routed IP. We've just bought a PIX to go right behind it and that'll do all the stateful stuff, plus NAT/PAT. So I just need to configure the Alcatel to just pass everything from one interface (inside) to the other (outside) and vice versa. Do I name both interfaces, or just refer to the outside, fixed, IP address?
I have some example scripts ("user.ini") that you can upload - got some of these from Zen, a UK based ISP, but no joy...can anyone help?

Joey,

Do you have static IP's available to assign them to the Pix firewall public interface ? Or will you be performing double NAT ?

Hi Chris
Yeah we have 217.158.192.96/28, with .96 as base, and .111 broadcast. The router currently has a framed IP assigned of 217.158.147.24
Joey

Search on the internet (google/yahoo) for documents about: SIP Spoofing. They should help you...

Greetz,
SixFive7