HOWEVER, I did some experimenting and found out the following: if you put a valid .unl file in the same directory, EPN works OK!!! This is true for all 3 "unlocked" maps you put in this thread.
Looks as if the unlocking procedures did unlock the map itself, but in order to activate EPN, unlocking code still must be present. EPN is here all the time, but somehow unlocking methods didn't affect it and it still requires unlock code to be present there in a classical manner. Probably IMG file contains 2 "locked maps", and until now no method removed lock code from "EPN part of IMG file". Any ideas?