It's not end of the world if invoices cannot be imported.
Many importers today have a way to choose which data to use in which database row from a normal csv file.
I use invoiceocean today.
But no panic over this feature...
Doesn't really work for me. Get an error while importing.
But I left it and edited the 83 clients in the database instead. Didn't take too long...
So, "bug" still there for us who wants to import clients with nordic letters.