Quan,
Before the SA doser is connected to the ProfiLux, you must first make sure you have the latest SA firmware version on the doser. Once that has been confirmed, connect to the SA doser via USB and change the mode to "Slave". This option is found at the bottom of the main screen. Save settings.
You can then disconnect from the doser and connect it to the controller. Once connected, the steps are the same as adding a PAB device, assign it and set the pump numbering if necessary.
Keep in mind that the Wifi will be disabled once the doser is set to slave mode. In order for you to access your doser settings, your ProfiLux will have to have an internet connection.