For Meteosat-10 / -9 and MTG-I1 it's possible to add a fourth spectrum channel "N" (besides R, G and B ) that will be displayed in the night side of the earth. For Meteosat satellites you can set this fourth spectrum channel for all the infrared bands("IR_039" and lower). For MTG-I1 this means from band "ir_38" and lower. If you want white clouds for the night side, than you have to set the inverse image.