DECLARE @SQL NVARCHAR(MAX) = N'
EXEC [YourDatabase]..sp_executesql N''CREATE USER [domain\bck_user] FOR LOGIN [domain\bck_user]''';
EXEC sp_executesql @SQL;
SET @SQL = N'
EXEC [YourDatabase]..sp_executesql N''EXEC sp_addrolemember N''''db_backupoperator'''', N''''domain\bck_user''''''';
EXEC sp_executesql @SQL;
