how to set up 4-4-5 forecasting in E1?

We are setting up forecasting in a 4-4-5 calendar format.    We are finding that when the end dates for the 5 week month happen to fall outside of the monthly dates, say the months of prior Junes would start on 5/29/2015 and 5-30-16  and is projected to start on 5/31/2017  it would end on 7/1/2017 with Sundays being the start date for the weeks.    When that happens we are getting blank forecasts in the 5 week months because the dates don't match the month of either the beginning or the ending date.    If we change the end date of the