Each plug-in has an ini file for setting options that are unique to the scanner(s) that the plug-in supports.  You specify which options are available by placing an ini file with the same root name as you plug-in DLL in the plug-in data directory (...\AppData\Silver Bullet Technology\Ranger\Plug-ins\YourPluginName\ ), and by setting UniqueOptionsXML values when Ranger calls your GetUniqueOptions() function.