Hello Roman,
actually the FSB pro csv files could be opened in excel. So just try the other way around. Save the files in csv, and try to place them in FSB Pro.
If not working open one sheet of excel from your broker, and one sheet of excel with the file you get when you use the script for FSB Pro.
If there are differences try to eliminate them, and make the same files. Than you should be able to use this Historical data from your broker in FSB Pro.