Assuming the bulletin board doesn’t have its own language directory you would access your en-GB.ini file to format the date.
*EDIT* Bulletin Board does come with admin and site language files, but neither deal with the date format from what I see. The below info should work for what you are asking.
/language/en-GB/en-GB.ini
PHP Date format information HERE
DATE_FORMAT_LC4=%M.%d.%Y
Original data:
<blockquote># Date format
DATE_FORMAT_LC=%A, %d %B %Y
DATE_FORMAT_LC1=%A, %d %B %Y
DATE_FORMAT_LC2=%A, %d %B %Y %H:%M
DATE_FORMAT_LC3=%d %B %Y
DATE_FORMAT_LC4=%d.%m.%y
DATE_FORMAT_JS1=y-m-d
%Y-%M-%D=%Y-%M-%D
%A, %B %E=%A, %B %e</blockquote>
Replace with:
<blockquote># Date format
DATE_FORMAT_LC=%A, %d %B %Y
DATE_FORMAT_LC1=%A, %d %B %Y
DATE_FORMAT_LC2=%A, %d %B %Y %H:%M
DATE_FORMAT_LC3=%d %B %Y
DATE_FORMAT_LC4=%M.%d.%Y
DATE_FORMAT_JS1=y-m-d
%Y-%M-%D=%Y-%M-%D
%A, %B %E=%A, %B %e</blockquote>
Hope this helps!