Updating DDBEA lockbox info with MSSQL admin GUI - supported?

Customer found a feature in the MSSQL Management GUI that appears to take care of adding and removing users for DDBEA in terms of putting their info into the lockbox - but after attempting to use it to change the DDboost user, a test backup we ran failed.

All of the "Data Domain side" steps for the new DDboost user were performed, and the actual "add user" feature did not throw any errors - but the backup job appeared to have issues accessing the Data Domain.

Also, side question - is the "config file" used for command line lockbox updating referenced at any time after it is used with the command line, or does it just serve to provide additional parameter input at the time the command is run?

All comments/feedback appreciated - thanks. (especially if anyone has actual instructions for changing or updating user/password information in DDBEA for SQL - they don't appear to exist anywhere)