Night Cabin Windows Repaint Project Airbus Help

Good afternoon,

I am trying to take out a few lit cabin windows on a project airbus aircraft on the L.bmp texture that appear at night where there are no windows.

I have DXTBmp and imagetool and a paint programme to do this and have been playing around with it a bit but keep having a problem that the cabin lights on the part of the fuselage I've edited only come on with the landing light switch.

I edited the texture l.bmp to black out the windows, but then the alpha channel shows as white which I know connects the cabin lights to the landing lights so I created a new black alpha channel but still having the same problem and a bit confused now on how to change it so the cabin lights are on all the time at night with being connected to the landing lights.

I managed to do it with a SkySpirit 777 without any problems but that must be a different format on how that works.

I'm not a painter and don't have any experience really so looking for any help from anyone as the alpha channel thing confuses me a bit.

Look forward to hearing from anyone and any help/tutorial that I can do.

Kind Regards

Gavin Moss