Hi Todd,
It's hard to give you an final solution cause of you did not provide us with format of stored string in your DB.
But you can try following solution:
pre
//This is your date string.
var stringDate = "03/22/2015";
//This is a date JS object.
var date = new Date(stringDate);
//Note: you need to replace "mobiledatepicker_2" with your datepicker component value.
var dateValue = $.datepicker.formatDate(Appery("mobiledatepicker_2").getAttr("dateFormat"), date);
//Note: you need to replace "mobiledatepicker_2" with your datepicker component value.
Appery("mobiledatepicker_2").setAttr("defaultDateValue", dateValue);
/pre
If it will not work for you please specify following things need to help you:
Returned by service date format(actually it's string in your case).
Date format in your date picker. Default is "mm/dd/yy".
Regards.