To manually modify a .HPJ file to include Natural Search, you need to make the following modifications:

Add the WinHelp macro for the Natural Search button using the following code:

[CONFIG]

RegisterRoutine(`SmaRTEng.dll',`SmaRTLookupEx',`SSSU'):CreateButton(`smartBtn',`N&atural Search',`SmaRTLookupEx(qchPath,` ',`Natural Search',hwndApp)')