How to set date format for DatePicker?

Hi! I use Designer 4.02. And I try to set DatePicker field with date. The date is the value which I got from RoleAssignmentBean. So, it is java.util.Date.getTime(). Then I set DatePicker field to date: field.setValues([new Date(effectiveTime)]). The date within datepicker looks like "Thu Aug 16 2012 12:38:28 GMT+0300 (EEST)". If I select another date via datepicker button then date is changes its format to "24.08.2012 12:00:00".
Can I set the second format by default? So that it looks like "24.08.2012 12:00:00".