FFVI: Veteran Edition

This may sound like a fairly simple question, but how can I make a chest contain a monster? I'm sure it requires hex editing, im just not sure how to find the chests in the rom, or how to specify the monster formation to use.

FF6LE let you place chests and you can have a monster-in-a-box if you want. FF6MDE let you manage existing chests too.

You can alternatively use an NPC for special locked chests and use an event to trigger a battle with a formation number between 256 and 511 that would be placed on the chest. The first solution (FF6LE or FF6MDE) is a lot less time consuming.