when i changed the dateformat in calendar.js
var CAL_DATE_FORMAT = "dd/mm/yyyy"; then the date format seems to be working fine.
But no java scripting events like onchange and onblur are generated on the inputtext component after selecting the date.
Same problem here...
When the date is rendered via AJAX it isn't a new page load so that portion isn't called, so CAL_DATE_FORMAT is undefined and the date is defaulted to MM/dd/yyyy as per line 12 of calendar.js.
The workaround is to add this block into your page (anywhere really) so CAL_DATE_FORMAT is set before the date is rendered via AJAX. Works for me anyway.