Jquery + datepicker - I just want to select Sunday, in the future

Hi everybody,
I’m trying to get the datepicker to only allow me select Sundays in the future. For some reason, I can select any Sunday, but can select days in the past. Here is my code.

	var dateGlobal = null;
	var dialog = null;
   			beforeShowDay: function(date) {
				var a = new Array();
				a[0] = date.getDay() == 0;
				a[1] = '';
				a[2] = '';
				return a;
	$('#inputdate').datepicker('option', {dateFormat: 'dd/mm/yy'});
	$('#inputdate').datepicker({minDate: '0'});

Seems the mindate function is not working?

If you can help, please tell me where I am going wrong.

Thanks in advance