All questions regarding mapmaking for Heroes of Might and Magic 3: The Shadow of Death.

How can I copy a part of a map? Or generate a separate dungeon. I have a single-level map. I want to add an underground area to it. Either from another map or just with a random generator. I found some program called "copymap" that works like a console command, but it doesn't work on 64-bit systems. I found something about attaching it to the editor, but only for WoG. I need it for SoD or HotA.