Sunlight system objects are not creatable by MAXScript.
A Sunlight system is comprised of a Compass Helper object and a TargetDirectionalLight object. The TargetDirectionalLight's transform is controlled by a set of float controllers, which are sub-controllers of a non-accessible position controller (a Sunlight_Slave_Controller position controller). These float controllers can be accessed as subAnims of the TargetDirectionalLight node. These float controllers, and their subAnim index number, are:
Solar_Time - subAnim[3]
Solar_Date - subAnim[4]
Latitude - subAnim[5]
Longitude - subAnim[6]
Orbital_Scale - subAnim[7]
For example, if node $Sun01 is the light for a Sunlight system, the Solar_Time controller can be accessed as:
solarTimeCont=$Sun01[3].object