Mentat Technologies Database Solutions

Hi,
I am a beginner,
I defined a simple stored procedure which contains two IN DateTime parameters shown in the following
CREATE DEFINER=`root`@`localhost` PROCEDURE `TimeDiff`(IN s_date DATETIME, IN e_date DATETIME)
BEGIN
DECLARE StartDate,EndDate DATETIME;
SET @StartDate= s_date;
SET @EndDate=e_date;
SET @UnitDate =(DATEDIFF(@EndDate,@StartDate));
select @UnitDate;
END
It works fine when Java calls this stored procedure or clicking ‘Run’ stored procedure in navicat tool. However,when I use DreamCoder , it’s strange to see datatype is unknown in the clip, and when I input date time in value, for an example, 2010-08-22, it doesn’t work even I try to change datatype to Date or TimeStamp.
Can anyone tell me how to use DreamCoder test tool to get the result ?

Any suggestions or hints will be appreciated.
Many thanks