How to apply water mark text on existing pdf file saved on disk

1.Actually iam using aspose.pdf older version 5.2.1.0..thts y iam not able to see document in intellisense of aspose.pdf....As per my requiremwnt iam geting bytes and converting to memrory stream and writing to pdf document which shown in below line

byte[] pdfBytes = File.ReadAllBytes(@"C:\output.PDF");

Aspose.Pdf.Document pdfDocument = new Aspose.Pdf.Document(new MemoryStream(pdfBytes));

2.As per your reply in the above specified post tht the given code is valid, when creating a PDF document from scratch using pre-6.x version of Aspose.Pdf for .NET.

i think tth above code will not work for my current requirement rite?and it is also not possible with out the above two lines of code in first point rite?so it is difficult to work in older version..so ur rly shows that it is not possible to work with Aspose.pdf with older version rite?

3.Is it possible to add watermark text to pdf file using aspose.pdf.kit version (5.5.0.0)..if possible can u pls provide me the code snippet ...related to my requirement...including tht two lines of code in first point....

actually i tried this below code using aspose.pdf.kit but there was a problem with input file..i dont want this input file...just i want to get bytes in memory stream and write to any pdf like the above two lines of code in first point and then passs to PDFFILEINFO... Can you pls modify the code as per my requirement using aspose.pdf.kit...

string inFile = @"C:\input.PDF";

string outFile = @"C:\kit.PDF";

// create PdfFileInfo object to get PDF file information

PdfFileInfo fileInfo = new PdfFileInfo(infile);

// create Stamp object

Stamp aStamp = new Stamp();

// create a sample formatting text with Maroon as font color and text size as 50

FormattedText formatted = new FormattedText("Draft Document", System.Drawing.Color.Maroon, Aspose.Pdf.Kit.FontStyle.HelveticaBold, EncodingType.Winansi, true, 50);

aStamp.BindLogo(formatted);

aStamp.IsBackground = false;

// specify the page number over which watermark should be displayed

// aStamp.Pages = new int[] { };

// Watermark rotation angle

aStamp.Rotation = 45;

// specify the opacity value for watermark

aStamp.Opacity = 0.5F;

//specifies the position of stamp

aStamp.SetOrigin(fileInfo.GetPageWidth(1) / 3, fileInfo.GetPageHeight(1) / 2);

PdfFileStamp stamper = new PdfFileStamp(inFile, outFile);

stamper.AddStamp(aStamp);

stamper.Close();