How can i enable solar modelling in radiation?

[Jyclub]

Hello, i am using Syrthes V5.0. I noticed that in the radiation options there is this solar modelling function bar, yet it's always grey and i could not enable it anyway. Like is shown in the attached screenshot. Can anyone kindly tell me how i can enable this function? Or is it not yet fully developed therefore still unavailable so far? Thanks in advance.