Cómo colocar las mismas firmas digitales en múltiples lugares en PDF usando itextsharp.net

He implementado la firma digital usando iTextSharp Dll para firmar archivos PDF con una sola firma creando campos de firma vacíos y actualizar el campo de firma con hash firmado funcionando bien. Ahora, quiero colocar la misma firma digital en cada página de pdf. Es el requisito de mi cliente.

Estoy usando el siguiente código:

public class MyExternalSignatureContainer : IExternalSignatureContainer
{
    private readonly byte[] signedBytes;

    public MyExternalSignatureContainer(byte[] signedBytes)
    {
        this.signedBytes = signedBytes;
    }

    public byte[] Sign(Stream data)
    {
        return signedBytes;
    }

    public void ModifySigningDictionary(PdfDictionary signDic)
    {
    }
}

Debajo del código usado en el programa

PdfReader reader = new PdfReader(unsignedPdf);
FileStream os = File.OpenWrite(tempPdf);
PdfStamper stamper = PdfStamper.CreateSignature(reader, os, '\0');
PdfSignatureAppearance appearance = stamper.SignatureAppearance;

appearance.Reason = "Reason1";
appearance.Contact = "";
appearance.Location = "Location1";
appearance.Acro6Layers = false;
appearance.Image = null;
appearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
appearance.SetVisibleSignature(new iTextSharp.text.Rectangle(36, 748, 144, 780), 1, null);
for (int i = 1; i < 8; i++)
{
    var signatureField = PdfFormField.CreateSignature(stamper.Writer);
    var signatureRect = new Rectangle(200, 200, 100, 100);
    signatureField.Put(PdfName.T, new PdfString("ClientSignature_"+i.ToString()));
    PdfIndirectReference PRef = stamper.Writer.PdfIndirectReference;
    signatureField.Put(PdfName.V, PRef);
    signatureField.Put(PdfName.F, new PdfNumber("132"));
    signatureField.SetWidget(signatureRect, null);
    signatureField.Put(PdfName.SUBTYPE, PdfName.WIDGET);

    PdfDictionary xobject1 = new PdfDictionary();
    PdfDictionary xobject2 = new PdfDictionary();
    xobject1.Put(PdfName.N, appearance.GetAppearance().IndirectReference);
    xobject2.Put(PdfName.AP, xobject1);
    signatureField.Put(PdfName.AP, xobject1);
    signatureField.SetPage();
    PdfDictionary xobject3 = new PdfDictionary();
    PdfDictionary xobject4 = new PdfDictionary();
    xobject4.Put(PdfName.FRM, appearance.GetAppearance().IndirectReference);
    xobject3.Put(PdfName.XOBJECT, xobject4);
    signatureField.Put(PdfName.DR, xobject3);

    stamper.AddAnnotation(signatureField, i);
}

IExternalSignatureContainer external = new ExternalBlankSignatureContainer(PdfName.ADOBE_PPKMS, PdfName.ADBE_PKCS7_DETACHED);
MakeSignature.SignExternalContainer(appearance, external, 8192);
stamper.Close();

byte[] SignedHash =  DoEsign(SHA256Managed.Create().ComputeHash(appearance.GetRangeStream());
os.close();
reader.close();

reader = new PdfReader(tempPdf))
os = File.OpenWrite(signedPdf)

IExternalSignatureContainer external1 = new MyExternalSignatureContainer(SignedHash);
MakeSignature.SignDeferred(reader, signatureFieldName, os, external1);
os.close();
reader.close();

Por favor sugiérame que complete la tarea

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