Hello!
Currently changing the language has no effect on the date picker since the days and months continue to be in English, probably because the jQuery ui initialization thing is separate from the LoadLanguage action.
It would be nice to be able to change both the month and days labels but also the format.
Changing the format to a fixed value was easy, I just modified:
jquery-ui.latest.js, line 7326
dateFormat: 'dd/mm/yy', // See format options on parseDate
And convertToDcm4cheeDate on newSearch.js
retVal = str[2] + str[1] + str[0];
And the date placeholders to dd/mm/yy for aesthetic reasons.
As nice as it is to be able to change the locale on the fly making the language configuration a fixed server side thing would make things much easier. Just a suggestion though.