How to add boil oil to Outposts? If possible (in tune pack)

Hi, does anyone know if it is possible to add boiling oil (aka murder holes) to outposts?

Basically adding weapons to other buildings is the general question. Perhaps the same way garrison arrows were added to houses for Delhi? Interestingly, there is a slot in the ebps for murder holes for the outpost, since they probably thought about the possibility. But it is “turned off” somewhere. I have been looking at the Murderholes in “upgrade” attributes, as well as comparing the ebps of the keeps, towers, and outposts. But I still cannot figure out how to enable it. Thanks for any suggestions!