Hi
First take Shstudio 0.7.5.2 because it's not working with 0.7.5.5 and go on the .wld you want to change.Then press shift+Insert on the category of your choice to add an object. (Need to extract the database first with DataFileTool) and choose the object in the right category.And now it's done
Need to add the location with shift+insert by clicking on the object you added. Hoping you will understand
(I'm sorry for english but i'm french guy)