Datepicker of CMS date field with configured format

We followed the steps in to change the (joda) date format of a Date field into ‘dd-MM-CCYY’ (to enforce cms users to explicitly specify the century). This works for manually entered dates, but via the datepicker popup the year gets lost (the date string becomes for example ‘21-02-CCYY’). Is there a way to get this working, or alternatively to hide the popup button? We use Hippo 11. Will this be the same in versions 12 or 13? As a fallback we may implement a custom validator that doesn’t accept dates from the zeroeth century at store time, but we would like to notify the user at an earlier stage.

As far as I know we (and all underlying frameworks we use, Jackrabbit/Wicket ) are using java date/time
so I don’t think that will work.