It seems that with the current UserType framework of Hibernate it is 
not possible to "correctly" implement the clob handling algorithms 
from Oracle.
Based on http://download-
west.oracle.com/docs/cd/B10501_01/java.920/a96654/oralob.htm#1043220
it seems that to write a clob you need to select the clob handler 
first, and then modify the clob handler. As far as I can see this is 
not possible to do in the set() method of af user type, as the inputs 
are a prepared statement to which we should bind the value to be 
inserted.

Or is it just me being daft? :)