Numberboard/Running number alpha problem

[RAILSOHIO]

I am finally getting around to finishing a re-skin of the NS SD 45 pack I started some time ago. I have read all the threads about alpha-ing out the cab numbers,but I am having a problem with the running board numbers fading after you zoom away from the engine. The SD 45 model has a 3 layer cab/ number texture. My usual DDS conversion is done with RW tools/DXT /Paint.net. I do the actual re paints with 2 other photo programs and import. I also have Gimp. Following the tutorial to alpha out the cab number with Gimp gives me a message that "It appears your image may be a volume map,but all images are not the same size,so the map can not be written. I blackened just the alpha for the cab number with other programs,and the cab number is absolutely gone,thats great. But I have the fading number boards,as I stated. Which leads to another question. Does a 3 layer number texture mean Color/stencil/reflectivity? I had done a lot of alpha editing in Trainz,but I am sort of stuck here.