It's easy now that I have one built...
By the way, these flags animate. They get installed in OpenZone's creature library and are exported as any other creature (but can be placed as doors). This method only works with SimpleClient but allows objects that use *skeletal* animation to be placed just like any other object in the doors table. My Lelembeth zone uses this method to place a couple of flags near an orc camp somewhere (though you need to use my sample DB to make them appear, see the doors table)...
I haven't tried using them with the live client, but I think it's theoretically possible if you create an NPC type for them, export the flag using the appropriate racial mnemonic (e.g. 'ORC') and set the NPC type so that it doesn't aggro and can't be attacked. Then place the flag like any other mob. Interesting exercise for the reader, but might be possible.