code: protected Timestamp eval(final Object[] _value)
          throws EFapsException
      {
          final Timestamp ret;
          if (_value == null || _value.length == 0 || _value[0] == null) {
              ret = null;
          } else  {
              final DateTime dateTime = DateTimeUtil.translateFromUI(_value[0]);
              // until now we have a time that depends on the timezone of the application server
              // to convert it in a timestamp for the efaps database the timezone information (mainly the offset)
              // must be removed. This is done by creating a local date with the same, date and time.
              // this guarantees that the datetime inserted into the database depends on the setting
              // in the configuration and not on the timezone for the application server.
              final DateTime localized = new DateTime(dateTime.getYear(),
                                                      dateTime.getMonthOfYear(),
                                                      dateTime.getDayOfMonth(),
                                                      dateTime.getHourOfDay(),
                                                      dateTime.getMinuteOfHour(),
                                                      dateTime.getSecondOfMinute(),
                                                      dateTime.getMillisOfSecond());
              ret = localized != null ? new Timestamp(localized.getMillis()) : null;
          }
          return ret;
      }
docs: The value that can be set is a Date, a DateTime or a String
  yyyy-MM-dd'T'HH:mm:ss.SSSZZ. It will be normalized to ISO Calender with
  TimeZone from SystemAttribute Admin_Common_DataBaseTimeZone. In case that
  the SystemAttribute is missing UTC will be used.
  
  @param _value value to evaluate
  @return evaluated value
  @throws EFapsException on error