Ok, finally I did it by myself.
Now everything is perfect: Kodi starts up automatically soon after Himedia booting, from Kodi when I choose one of my videos or Tv series they are played directly by the Himedia player, instead when I choose a stream or IPTV they are displayed automatically by the Kodi player.
Here are the steps I followed:
- normal installation of the wrapper and activation of the playercorefactory.xml that is with it
- launch file manager (explorer), shows hidden folder, copy the new playercorefactory.xml, go in the right folder android/data/org.xbmc.kodi/files/kodi/userdata and press copy file, here pops up a windows that ask if you would like to overwrite the existing .xml file, press YES and now you can enjoy this wonderful HiMedia Player