hi guys!
there is no way to ungrey those fields for me..., but u can solve this in other way:
in outliner uncheck Display>DAG nodes only, then find maxwellEnvironment and run channelbox on the right
now u can change all the parameters... but there is an issue with days/months/years coz it julian... so u need to count all days from the beginning of the year and input into Phy Sky Julian Day and actual day of the month into Phy Sky Julian Month Day

The Phy Sky Julian Month is obvious
anyway, hope that helps
update: after erasing all maya settings and creating new scene everything is ok
