It's not too complicated:
1. Put a PlaceHolder control on the page (this will help you to position the calendar).
2. Create the control in the Page_Load method and add it to the Controls collection of the placeholder:
protected void Page_Load(object sender, EventArgs e)
{
DayPilotCalendar dpc = new DayPilotCalendar();
PlaceHolder1.Controls.Add(dpc);
}
This will add an empty control. You can modify it by setting the properties. You just have to set them in the Page_Load instead of int the .aspx template.