use Date values in ExpressionFactory.exp

Hi!

Is it possible to use Date values in ExpressionFactory.exp?

This works very well:

Expression exp = ExpressionFactory.exp("businessPartnerName='andrea' and businessPartnerCode!='rossi' or ((businessPartnerCode!='bianchi' and maxAdvancePaymentPercent>9) or businessPartnerCode!='pippo' or (maxAdvancePaymentPercent>100 or maxAdvancePaymentPercent<10))");

but if I use a Date value like this:

Expression expDate = ExpressionFactory.exp("modifiedDate> '2003-07-17'");

The database, Oracle in my case, will complain:

Literal does not match format string 
(the database expects something like this:  MODIFIED_DATE > DATE '2003-07-17')

Any input?

Andrea