Has anyone successfully modded the DLC content for this game?

I've been trying to mod the DotB content, both with Hazard's Mod Manager and WinRed Package manager, but so far nothing's worked. Whenever I make any changes, DotB disappears from the Bonus Missions menu.

Am I missing something? Is there some file like table.vpp that I need to delete to get DLC mods to work?

I tried briefly as well, but couldn't get it working. Most of the time it disappeared from the menu as you said. A few times I got it to stay in the menu, but the game crashed when I loaded it.