1) You need to extract the current eu2 map data first:
This will create a "file.eu2map" containing the needed data, and the image of lightmap1, but not of the 2 others. Leaving away the /1 will include both lightmap2 and lightmap3, but that's not necessary.
However, this assumes you have EU2 installed on that machine. Since this might not be the case, or mextract fails to find the location, there also is a /D option for specifying the root directory.
Code:
mextract <file> /1 /D:<dir>
The specified directory must contain a Map and DB directory, like the normal EU2 installation would have.