Cuando intento este código para crear un PDF en árabe con C #, el archivo PDF generado contiene caracteres discretos. ¿Alguna ayuda para que no pueda obtener caracteres continuos?

//Create our document object
Document Doc = new Document(PageSize.LETTER);

//Create our file stream
using (FileStream fs = new FileStream(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test.pdf"), FileMode.Create, FileAccess.Write, FileShare.Read))
{
    //Bind PDF writer to document and stream
    PdfWriter writer = PdfWriter.GetInstance(Doc, fs);

    //Open document for writing
    Doc.Open();

    //Add a page
    Doc.NewPage();

    //Full path to the Unicode Arial file
    string ARIALUNI_TFF = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Fonts), "arabtype.TTF");

    //Create a base font object making sure to specify IDENTITY-H
    BaseFont bf = BaseFont.CreateFont(ARIALUNI_TFF, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);

    //Create a specific font object
    iTextSharp.text.Font f = new iTextSharp.text.Font(bf, 12, iTextSharp.text.Font.NORMAL);

    //Write some text, the last character is 0x0278 - LATIN SMALL LETTER PHI
    Doc.Add(new Phrase("This is a ميسو ɸ", f));

    //Write some more text, the last character is 0x0682 - ARABIC LETTER HAH WITH TWO DOTS VERTICAL ABOVE
    Doc.Add(new Phrase("Hello\u0682", f));

    //Close the PDF
    Doc.Close();
}