javascript - How to create a KnockoutJS Custom Binding for Date

Question

I have created the following js fiddle http://jsfiddle.net/pltaylor3/DsJKp/ to attempt to bind the dates that MVC4 creates to a user editable date that can be sent back to the server as well. My date is displaying properly but when I edit the date it does not appear to update the knockout model. What am I missing from my custom binding to update the Knockout model. I know there is some logic missing for updating the day and year but the month should be updatable.