Anyone know how to make a nav ladder without generating the whole mesh?

I have spent hours and hours reworking the nav mesh so that the bots use my map more effectively.

Unfortunately, I noticed that one of the ladders doesn't have a mesh on it. The footer information is there, but not the ladder matrix itself. It's possible that at some point, I accidentally deleted it.

Is there a way to define a ladder, or a way to edit the nav file, directly, that will allow me to recreate the ladder nav data, without having to completely reconstruct the entire nav mesh, the place names, the jump and crouch points.... without redoing the entire nav mesh?

Does anyone know the data structure used in the file? I was thinking of generating a new nav file, saving a copy under a new name, editing the nav mesh to delete the ladder, then doing a compare on the files to find the difference, then manually copying the data from one file to the other. Any thoughts would be appreciated.

Thanks

Apparently the engine will recognize ladders, and create the right nav data if you're precise in defining the ladder with begin_ and end_ area commands. I must have not been accurate enough in defining the ladder surface.