How to switch the Language in the Datepicker of Form Toolkit

I would like to know where in the PHP code of the Datepicker do I need to change to make the months and days appear in a different language? I am wanting to display the datepicker in Portuguese.

see this thread for details:
showthread.php?t=17433&highlight=format

Thanks Jason for the reply, but I not wanting to change the format, but the actual place where it says the names of the months on the Calendar as: January to Janeiro, February to Fevereiro and so on. Also the day where it says Mon to Seg, Tue to Ter, Wed to Qua and so on.

If you could place let me know on what lines in the PHP to change this, it would be much appreciated.

Thanks

add a monthNames option after the dateFormat setting. fro example:
$(function(){
$('#datepicker_1').datepicker({
dateFormat: 'mm/dd/yy',
monthNames: ['Januar','Februar','Marts','April','Maj','Juni','Juli','August','September','Oktober','November','December'],
showAnim: 'show',
onClose: closeDatePicker_datepicker_1
});
});