Formula To Calculate How Many Days In A Month And Create Column For Each Day

Formula which can calculate how many days in a month and create a column for each day. Columns for day 28, 29, 30 or 31 also need the formulas in columns 1 to 27 copied over automatically. [sheet name "LARSheet1 to 1" ]

I'm trying to build "Leave, Attendance Management" system using Excel. I am about 40% there so far.

The basic structure of the workbook is as follows:

12x main monthly "Leave Attendance Record" worksheets (i.emonths April 2012 through to March 2013). [I will refer to these sheets asLARSheet1 to LARSheet12 ].
1 x worksheet which holds "data validation" list andvlook up info. ["FormulaListSheet"]
1 x worksheet acting as a database of staff details andpay numbers. ["StaffdBaseSheet"]
1 x summary page which shows staff reaming leaveallocation. ["SummaryLeaveSheet"]

What I'm having problems with at the moment is as follows:

A formula or a macro which works out how many days are present in a given month [starting date of month located in CELL B10].

Days 1-27 will be already set up on the sheet. Based upon the monthly value I would like a solution which can calculate how many days are in a month and create a column for days 28, 29, 30 or 31 (depending on the month).

I would like it to work like this:

When the user opens a new worksheet, they first entre the month start date in CELL B10. Hopefully this will trigger columns E13:AH22 to update with the relevant week day & date.

I also need the formulas and formatting in cells AH13:AH100 (column for day 27) to copied over automatically.

Sample of sheet setup : screenshot_LARSheet1.PNG