The following characters are recognized to create the formatting:
%aabbreviated weekday name according to the current locale
%Afull weekday name according to the current locale
%babbreviated month name according to the current locale
%Bfull month name according to the current locale
%cpreferred date and time representation for the current locale
%Ccentury number (the year divided by 100 and truncated to an integer, range 00 to 99)
%dday of the month as a decimal number (range 01 to 31)
%Dsame as %m/%d/%y
%eday of the month as a decimal number, a single digit is preceded by a space (range ' 1' to '31')
%glike %G, but without the century.
%GThe 4-digit year corresponding to the ISO week number (see %V). This has the same format and value as %Y, except that if the ISO week number belongs to the previous or next year, that year is used instead.
%hsame as %b
%Hhour as a decimal number using a 24-hour clock (range 00 to 23)
%Ihour as a decimal number using a 12-hour clock (range 01 to 12)
%jday of the year as a decimal number (range 001 to 366)
%mmonth as a decimal number (range 01 to 12)
%Mminute as a decimal number
%nnewline character
%peither `am' or `pm' according to the given time value, or the corresponding value for the current locale
%rtime in a.m. and p.m. notation
%Rtime in 24 hour notation
%Ssecond as a decimal number
%ttab character
%Tcurrent time, equal to %H:%M:%S
%uweekday as a decimal number [1,7], with 1 representing Monday
%Uweek number of the current year as a decimal number, starting with the first Sunday as the first day of the first week
%VThe ISO 8601:1988 week number of the current year as a decimal number, range 01 to 53, where week 1 is the first week that has at least 4 days in the current year, and with Monday as the first day of the week. (Use %G or %g for the year component that corresponds to the week number for the specified timestamp.)
%Wweek number of the current year as a decimal number, starting with the first Monday as the first day of the first week
%wday of the week as a decimal, Sunday being 0
%xpreferred date representation for the current locale without the time
%Xpreferred time representation for the current locale without the date
%yyear as a decimal number without a century (range 00 to 99)
%Yyear as a decimal number including the century
%Ztime zone or name or abbreviation
%%a literal `%' character


Here is an example:
Input: %a, %d %b %Y %H.%M.%S +0000
Result: Tue, 06 Feb 2007 20.18.04 +0000

NOTE: You cannot use the colon « : » since it used by Métamorphose to denote the start of special operations.