I have the same problem. For me, the text entered on the dashboard is entered into an SQL database via a REST interface. But there I have the problem with characters like ÄÖÜß etc. that they are not stored in the database as ÄÖÜß.
My workaround is to convert the data in the dashboard to JSON. Then into a UTF8 byte stream. This is transmitted and returned in the REST interface from byte to JSON etc.