使用iTextSharp / iText将表添加到预先存在的PDF

I need to add a table using iTextSharp (or even PDFSharp if it can do it) into an existing PDF template at a particular location in the template. I can edit the existing template with Adobe Designer 7.0. How can I go about doing this? Is there a PlaceHolder analog from Asp.Net which can be used here?I need to add a table using iTextSharp (or even