public override DatumTransformation GetInverse()

{
  // Create from wkid
  HVDatumTransformation hv110018 = HVDatumTransformation.Create(110018);
  int wkid = hv110018.Wkid;
  bool isForward = hv110018.IsForward;    // isForward = true
  string name = hv110018.Name;            // Name = WGS_1984_To_WGS_1984_EGM2008_1x1_Height

  // Create from wkt
  string wkt = hv110018.Wkt;
  HVDatumTransformation hv110018FromWkt = HVDatumTransformation.Create(wkt);

  // Get the inverse
  HVDatumTransformation hv110018Inverse =
     hv110018.GetInverse() as HVDatumTransformation;
  // hv110018Inverse.IsForward = false
}