Customize RadSheduler: i want to change Weekview from 7 days to 4 days

[BUI]

i want to buil a shaeduler with 4 days in viewmode = weekview
the code in  .cs
protected void Page_Load(object sender, EventArgs e)
        {
            DateTime datenow = DateTime.Now.Date;
            RadScheduler1.SelectedDate = datenow;
            doDates();
      }
......

protected void doDates()
        {
            DateTime datenow = RadScheduler1.SelectedDate;
            DateTime firstday = datenow.AddDays(-1);
            DateTime endday = datenow.AddDays(2);
            DayOfWeek firstdayofWeek = firstday.DayOfWeek;
            DayOfWeek enddayofWeek = endday.DayOfWeek;
            RadScheduler1.FirstDayOfWeek = firstdayofWeek;
            RadScheduler1.LastDayOfWeek = enddayofWeek;

        }
the problem is when I change "today" in the calendar of scheduler, it does not change automatically RadScheduler1.FirstDayOfWeek and RadScheduler1.LastDayOfWeek but retains all the time 4 days.
This process what happens in the code of telerik and I can not change.
I need help for this problem.

Thanks

[BUI]

i use web service for building data for rad scheduler.