How to add night texture in photoreal ?

I have created photoreal for a vast region with 140 tiles with sbuilderx. If I try to load night texture thats _LM via sbuilder, it takes forever for a file to load.

I tried editing INF file and added LM via that, then used resampler.exe to compile to BGL. It processed Day and night but when I checked in FSX, only day shows up even during night time.

How do Photoreal scenery developers create night textures for a vast city region?