Excel 2007 : Auto complete shift roster

Hi,
I have been trying to auto complete a shift pattern onto a made up calendar without much success.

Please see attached Excel workbook.

The calendar side of it works OK & by entering the date in box AH3 the days of the month auto fill OK. It may not be pretty as far as formulas go but it works OK & gives me a printable 6 month view on a single sheet.

I now need to get it to fill in the shift pattern. I don’t need it to roll over from year to year. I would like to enter the first day of the year & have it auto complete to the end of that year from there if possible.

The pattern is a rolling 28 day cycle. The working cycle & the day’s off cycle always start on a Thursday.

(Looking at the 2013 page)
2012 ends with 12 “W” days, so 2013 will have to start with 16 “W” days to complete the 28 day cycle. I have added boxes AJ3 & AJ5 to manually enter the number of “W” or “O” days completed from the previous year if this helps to work things out?

Cheers

John