Ok, I've got the new MFD to display the same as the existing CRT display. I did this by changing the texture of the new MFD surface to be the same one used by the main CRT. The file I selected in LW is a TGA file, and I converted the objects with the TGA file, and it works. However, I know that the textures.bin contains the BMP version of the file with the same name, so it might be ignoring the TGA file from LW, and using the BMP file. I also think this, as the texture folder does not contain the required TGA file. I think there might be some caching in memory as well, as earlier I got an error when I deleted the texture file, and now I'm not.
But I'm not going to worry about that for now.
I'm going to experiment some more, by changing the main CRT to use the new texture file, and see if I can get it to work the other way round.