From within your map in Terrain Builder: File > Import > Objects.Copy the contents of the clipboard in a file and save it with the extension.To do this you'll first need to drop the SCAR_E2TB_Module in your mission. From within a mission (SP): run the action Copy the map objects to the clipboard or the absolute position alternative.
You can check out results in this comparison image: If you have tried to import from EDEN or from any other custom tools that generate objects while in mission to Terrain Builder, you may have seen the hassle of objects' rotations being often incorrect. E2TB is a small module for Arma 3 that allows you to export data to Terrain Builder.