I’ve done it. Took me less than 10 minutes, including some figuring out.
From the Volvo manual under "Key Management":
Key Management
Adding or removing a key to or from the system can be done in either the Battery Control Panel or the 2.5", 4" and 7" displays. A system can have up to four keys, which are numbered from 1-4.
Adding a key
1 Navigate to the menu Settings > Key Management.
2 When the text Show e-Key For Authorization is shown hold a key that is already registered in front of the key panel. The system will check that the key ID corresponds to a key registered in the system.
3 Select Add a key.
4 When the text Show e-Key To Add is shown hold the new key in front of the panel. The system will store the key ID.
5 The addition of the key is confirmed on the display.
John