Offline map source created using MOBAC does not show up in OruxMaps

[GPSusr]

I have created an offline map using MOBAC, and copied the folder to

Internal shared storage > oruxmaps > mapfiles

There I have the following structure:

MAP_NAME >
  Layer >
    Layer.otrk2.xml
    OruxMapsImage.db

I also tried skipping the "Layer" directory, i.e. using:

MAP_NAME >
  Layer.otrk2.xml
  OruxMapsImage.db

In orux maps, I then chose the map icon, the "offline", and then the refresh button, but I keep just seeing "world".

How can I properly add an offline map?