FSX NIGHT SCENERY (question 2)

Dearest Ian.
I'm sure you know FSX perfectly and I have to ask you how to make an object (exemple "house") "night" in FSX.
My procedure:
1) I build a house in 3D with the Sketch-Up program (house. SKP)
2) I export the house in 3D with the “Collada” subprogram (house.DAE)
3) I use the ModelConverterX program which:
a) Transform the textures from JPG format into DDS format rotated by 180°
b) Change the dimensions to quadratic formats (example 128x128 px or 256x128 px ...)
c) Generate the complete object in MDL format (house.MDL)
4) With the ADE program I insert the “house.MDL” model into the airport map.
This produces the desired result in the DAY condition.To view the inserted object (house.MDL) AT NIGHT, I can do this:
5) With the Photoshop program I change the color of a texture (for example “wall_.JPG”) and rotate it 180°.
6) Knowing that FSX can understand if a texture must be used at night by inserting the acronym “LM” in the file name,
I save the new texture with the name “wall_LM.JPG
7) With an online program (Convertio) I transform “wall_LM.JPG” into “wall_LM.DDS”. In the FSX Addon Scenery I insert this new texture into the appropriate “stexture” folder.At this point I should see the “wall_.DDS” texture during the day and the “wall_LM.DDS” texture at night.
Unfortunately this simple procedure doesn't work and I don't understand why.
I'm sure you can help me.
Thank you very much and bye.
Gulliver.