I finally discovered the refresh "button" which made the new map file recognized.
Another question regarding maps:
I downloaded the World_OSM map and installed it too.
Now I have a problem because OruxMaps seems to prefer this map even though it is not as detailed as the specific maps I have downloaded for areas of interest to me.
Is there a way to tell OruxMaps to use the World_OSM map only if there is no specific map for the area???