I have tested the unicode behavior and it is working with some changes to your mapping. The easiest way is to globally change the mapping for string to NVARCHAR. This can be done in the backend configuration settings of your app.config file. You have to have this nodes:
backendconfiguration id="mysqlConfiguration" backend="mysql">
The NVARCHAR string is not choosable from the forward mapping dialog, we will change that.
I have attached my sample project that is working with mysql.
the Telerik team