If you use the calendar option, the date part of the datetime is displayed with the help of the JQuery DateTimePicker, So in addition to the normal globalization setting you have to add a specific call that globalize the jquery calendar:
<%: Html.JQueryDatePickerGlobalizationScript() %>
pls, refer to the documentation fro the complete infos on this function: http://mvccontrolstoolkit.codeplex.com/wikipage?title=DateTimeInput%20and%20DateRange%20attribute
This have to be placed at the start of your page after the jqueryUY scrip as per examples included with the binaries.
Unluckly, the globalization of the JQuery calendar is not very well supported, so maybe your culture is not supported so JQuery calendar fall back to en-US.
In the documentation you will find the list of all supported cultures.
We are working to compute automatically the settings needed by the jquery calendar by the normal culture setting that are better supported,
in the meantime if your culture is not supported you have three choices:
1) you don't use the calendar option. In this case normal globalization settings are enough, and probably your culture will be included since normal globalization settings
use either the "global" library or the Microsoft ajax library depending on if you use Mvc3 with unobtrusive ajax or not. Both libraries are well supported,
and contains hundreds of cultures, so your culture should be included.
2) pass manually one of the culture supported by the JQuery calendar to the function Html.JQueryDatePickerGlobalizationScript.
Probably there is another english culture with the same settings...so you can solve this way. Here the list of all cultures supported by the jQuery
datetime picker: http://jquery-ui.googlecode.com/svn/trunk/ui/i18n/ As you can see it is not very long......
3) define yourself the culture file of your culture by just correcting the en-US, then you use it yourself and submit it to JQUERY, so also other people of your
country nay benefit of it.