Q: Is it possible to use MySQL 5 databases?
A: Yes, this is fully supported. You need to install a ODBC driver 3.51 or 5 to be able to connect to such a database.

Q: We need to store metadata in Unicode. Is this supported with MySQL 5?
A: MySQL 5 supports unicode but unfortunately thie ODBC driver 3.51 is not able to handle unicode. Therefore you need to install a ODBC driver version 5.x for connecting to such database.

Before doing this please be sure that you downloaded and install the newest SQLAdmin section from this forum.
Hint: You should never change the SQLAdmin for MySQL driver version 3.51 to unicode (NTEXT, NVARCHAR). This will never work!

External link to the drivers: http://dev.mysql.com/downloads/connector/odbc/5.1.html#win32