The Kamstrup SigFox add screen requires you to upload an XML file.
This is because the device encrypts it's readings.
Specifically there is a value called DEK in the file.
You should have received this XML file when you bought the device.
You would have also received a CSV file that contains the mapping from the SigFox serial to the Kamtrup serial.

In the add dialog, you can add one SigFox device, if you can manually extract the DEK from the XML file (open the file a browser)

alternatively, you can attach the XML and CSV files in the add dialog to do a bulk add.


Also, if you somehow captured the wrong DEK for a meter, you can change that under Edit->Meter Details->Password


Also, all SigFox packets are saved AS IS, so if you need to re-parse the data, you can just
-set back the meter
-delete the totals
-reread the meter