For Prontera, the closest thing you can do is:
Lightbulb 1:
RGB: 0, 0, 0
Intensity: 127 (For a lighter shadow effect change this value to 192 and keep lightbulb 2 at 127)
Cast Shadows: No
Falloff: 0.01
Radius: 20,000
Lightbulb 2:
RGB: 0, 0, 0
Intensity: 127
Cast Shadows: Yes
Falloff: 0.01
Radius: 20,000
Place lightbulb 1 in the middle of the map and raise it up. Place lightbulb 2 at the bottom left hand corner of Prontera and raise it up. Generate -> Calculate lightmaps and hopefully it will give a similar result.
Note: Ensure that your Global Lighting Parameters (Windows -> Global Lighting) match Prontera's.(See Attached Image)