I'd like to ask if this is possible, and if so, how I'd go about doing it.

A have a room split in half with a horizontal line. From the west, the upper half is accessible through a normal passageway door, but I want the lower half to be accessed through a locked door. However, because the Tools->Doors option always places doors in the center of the sides of the room, I can't use that option. Is it possible to configure manual locked doors, and if so, how?

For the record, I'm using the 1.92 Beta (build 182), and am using Mr.Z's Pure Tileset Update Extreme.