InfoPath Forms Services : Date Picker in a european Format

[Stephane.ch]

Hi,
I am faced to a problem. I designed a form including 2 date pickers.
When I open it in Infopath, I can the select date in a european format
(Weeks start on Monday), but when I open it in the browser, the
calendar appears in a american format (weeks start on sunday) and in
french (-as expected-).

How can I set the calendar format in InfoPath Forms Services for date
picker so that week start on monday?
Thanks