Column Heading in Crosstab

I have a crosstab that contains dates grouped by week as the column. Since it is grouped by week it gives Sunday as the start date of the week. Does anyone know how I can change it so that it will show Monday as the beginning of the week?Create a formula having this code
weekdayname(weekday({datefield})+1)
Now Group the report by this formula|||I tried this formula in my crosstab and it seperated the columns into Monday, Tuesday, Wednesday etc. I need it to show the dates. For example, what it shows across the top now is:

6/5/05 6/12/05 6/19/05 6/26/05

what I need it to show is the week starting on Monday:

6/6/05 6/13/05 6/20/05 6/27/05

Any help would be appreciated.