Amazing, wasn't aware of the fact that Corona is able to render that "physical Sun&Sky" map and that sun as well? What "sun" and "sky" is this now? Corona sun in disguise? Even caustics are working with it.
Basically I'm not looking for support for the render stamp directly at all, this is easily doable by script. The problem with the legacy daylight system is, that you cannot access the date correctly.
So I was hoping to get a replacement for the daylight system working like one in every aspect, but easier to handle and with proper script access. What I get now when using the sunpositioner is a sun which does not show up in any light lister (because it's only there at render time?), cannot be added to a lightselect element (meaning isolated, the sun is always part of environment) and does not offer Corona sun/sky specific properties. Probably the concept of that sun positioner is so different (combining sun + sky to "environment") that it's not fitting well into traditional treatment of a scene, even from a renderers point of view?
Good Luck