Need Formattig for specific date format in datepicker

Hi, 

I want to add a specific data format in the date picker edit field.

I tried the following method but it won't work

`{"column": 2,
                "type": "datepicker",
                "options": {
                    "icon": "http://jqueryui.com/resources/demos/datepicker/images/calendar.gif", 
                    "dateFormat" : 'dd-M-yy',
                }`

Thanks