Making a BG2EE map area visitable

[nullset]

I need to make a map area visitable using scripting actions. I know it can be done, because I see the game converting grey map areas to colored all the time. I cannot find how to do it myself. I have found the script actions to reveal/hide an area, but the visitablitily eludes me. I know where the controlling bit is in the map/area structure, so I can control this pre-game launch. I want to do it inside the game. Anybody out there know how to do this? All help gratefully accepted.

[Mike1072]

AddWorldmapAreaFlag? I think it's the EXPLORABLE flag you want.