Ok, I believe you may have to convert that field to a TIMESTAMP in order for it to register with querying drivers as a field that contains both Date and Time portions. 10g also has TIMESTAMP WITH TIME ZONE and TIMESTAMP WITH LOCAL TIMEZONE types, but I'll leave that determination to you.
TIMESTAMP is an extension of the DATE datatype, designed to include the additional information. Technically the DATE datatype in Oracle does store time information, but I believe the standardized solution for you is to make the datatype universally visible as a date/Time structure. The ANSI literal for DATE does not include time information ('2008-05-28'), so you end up having to use special Oracle-specific functions (TO_DATE) to specify time information. You don't want to do that. You want your application to be as portable as possible. TIMESTAMP also offers further granularity. DATE's time information only goes down to the second. TIMESTAMP to the millisecond. Better for determining intervals between operations recorded inside of a second.
If you want to read a little more, see...
http://www.stanford.edu/dept/itss/docs/oracle/10g/server.101/b10759/sql_elements001.htm Find the text "DATE Datatype" and read that and the "TIMESTAMP Datatype" below it.
I think if you use TIMESTAMP, and then use the code I posted earlier, you'll be good to go. I almost always have time fields in business objects declared as java.sql.Timestamp for this very reason.
Good luck... let me know if you have anything else.
nomad