Yes, you could use double NAT just as your ScreenOS is configured. The destination example is on page 23 of the document.
The other possibility is to convert the double NAT into a static NAT instead. This can be done if the device invovled is the only one using this ip address. You cannot split ports between multiple devices with Static NAT. The ScreenOS equivilent is MIP. Those instructions are on page 17.