This issue originated from
WeblogPlugin contains the following non localized date time format:
entryFormat - how to display the date on pages, using the J2SE SimpleDateFormat syntax. Defaults to the current locale's DateFormat.LONG format for the date, and current locale's DateFormat.SHORT for the time. Thus, for the US locale this will print dates similar to this: September 4, 2005 11:54 PM.
This ignores the user's prefered Date/Time format.
I propose to change it to revert to the user's prefered Date/Time format as the default (instead of the Java environment locale).