If you are presently using FireWall-1 and plan to use a similar security policy on SunScreen, you have two ways to do this:
You can convert the FireWall-1 machine to become the SunScreen Screen.
You can convert the FireWall-1 security policies and use them on a SunScreen machine.
Conversion instructions are in "Converting FireWall-1 to SunScreen in Routing Mode.".