This operation method is defined by ESRI:
Of particular interest the meaning of "Auxiliary Sphere Type" parameter:
- 0 = use semimajor axis or radius of the geographic coordinate system
- 1 = use semiminor axis or radius
- 2 = calculate and use authalic radius
- 3 = use authalic radius and convert geodetic latitudes to authalic latitudes
Types 0 to 2 are easy, type 3 is more tricky and may not be supported in the first version. Type 0 is equivalent to "Popular Visualisation Pseudo Mercator" projection method.