The DSON importer was never included in DS or as part of the Genesis/G2 figures. It is a separate product that has the Genesis and G2 figures bundled with it. The importer was created several months after the release of DS4. Genesis and the G2 line use the DAZ proprietary Triax rigging. The G3 line uses dual quaternion rigging and UDIM mapping whereas the older figures use standard UV mapping. If SMS opts to add support for dual quaternion rigging and UDIM in a future release of Poser, the G3 line might become Poser compatible.