netscreen 5 gt more than one ip

Hi
Im in doubt... I can't figure out how I setup my netscreen 5 gt so i
can have 2 or my external ip's? I got the numbers from my ISP so that
ok but how to set it up? Can anyone tell me how I do it? I would like
if I could get to or more lokal net. But first of all, I want to have
to servers on each with seprate ip adresse. One for mail and one for
web.
Is that possible?
Hmmm hope you can help me :-D