Editing Media Bay attributes

The MediaBay in Nuendo 11 doesn’t let me type into the fields for “Category Post” or “Musical / Category”, only choose pre-set attributes. Since these pre-set entries aren’t helpful, the MediaBay is useless to me for sorting sound recordings and effects.
Can someone tell me how to edit these pre-set lists? I remember being able to edit XMLs in previous versions, but can’t find them in this installation anymore.

Check out my post here!

Hm, I’m afraid I can’t find the files in question on a Windows system. Does anyone know where they are?