I have encountered problem with text encoding in MySQL.
This is now fixed; MySql package performs necessary conversion to default encoding.
However, this needs reconsideration of BLOBs in database (because they must NOT be converted). On fetch, U++ can deal with problem, but sending data to MySQL you have to embed it to SqlRaw helper type (just like in Oracle).
(Note that everything works by setting MySQL to utf-8 mode, therefore if your application is in utf-8 too, there is no conversion and no BLOB issue).