Problem with CLOBS and Qt OCI database driver

It seems that the Qt OCI database driver can't write properly data into a sql field in the database of type CLOB. The problem seems to be caused by the mapping between OCI data types and Qt data types. The mapping from sql data types to QVariant values (reading from database) is right. The CLOB data type and the BLOB data type will be mapped to the QByteArray data type, but the mapping from QVariant values to the sql data types (writing to database) is the problem: The QByteArray will only be mapped to the BLOB data type but NOT to the CLOB data type. This results in a binary representation of the character string like "54657374" in the database AND the model (and the gui).