Starting with the upcoming Ubersetzung release, this tool is obsolete. CUSTOM can import HS files directly. Windows users can drag-and-drop both your RPG file and your compiled HS file onto CUSTOM at the same time. Command-line users can type:
custom mygame.rpg myscript.hs
HS Importer is a utility written by TeeEmCee which can import a compiled plotscript HS file directly into a RPG format file without the need to open the RPG file in CUSTOM.EXE , which can be a big time saver if you are working on complicated scripts that require a lot of debugging.