[V8i Ss2/4] Power InRoads - Can we use Ss4 Geo Coordinates in Ss2?

We are using Power InRoads exclusively but have need to sometimes use Ss2 and other times use Ss4. These products use their own CAD Engine, Unlike InRoads Ss2 and Ss4. We have started using one of the newer Geographic Coordinates that is available in Ss4 but it is not in Ss2. Is there a way to copy the Ss4 files so they are available in Ss2 or do we have to create a custom coordinate system?