How to do it?

Well, I don't know WoG that well, and I haven't played maps in WoG for 7 years, only in SoD/Complete Collection. So, it's best to ask for help on forums where WoG and other mod developers, modders, and players communicate, for example, http://wforum.heroes35.net/index.php?language=russian or http://forum.df2.ru/index.php?showforum=4.