Custom wall object not aligning to tile ends

[Caulifloral]

Hi, I am trying to create some custom objects that are part of the wall category (and thus should align against the sides of a 1x1 tile). No matter what I try, the 'wall' object ends up in the middle of the tile rather than against the side/boundary as I open it in the Scenario Editor. I have tried to push it against the tile boundaries in the object editor in different variations, and have checked whether the other things are right and checked as such. I cannot find what I am doing wrong, has anybody else had this problem? Thanks in advance!