1. In export_obj.py, change line 413 from "me.calcNormals()" to "pass #me.calcNormals()"
2. Import with import_moi.py
3. Edit your object: add/edit UVs, materials, taxtures, etc. Do not apply modifiers or move a vertex/face!
4. Export to OBJ and enable the Normals button.
5. Leave the HQ button off as it doesn't really calculate any high quality normals, it simply recalculates them.

Make sure your application/renderer will read the normals from the OBJ file (the lines that start with "vn") and actually use them instead of recalculating them.