How to set the a Signature to have an image and text?

I am adding Digital Signatures to a PDF, and I want the appearance to be an image with vector (scalable) text over top. How can I do that?

The following code will set the appearance of any annotation with your image and your text over top.

static void SetAnnotationAppearance(PDFDoc doc, Page page, Annot annot, string imagePath, string text)
using(PDFDoc tempPdfDoc = new PDFDoc())
pdftron.PDF.Convert.ToPdf(tempPdfDoc, imagePath); // this call takes care of image DPI and image rotation
pdftron.PDF.Page tempPage = tempPdfDoc.GetPage(1);
using (Stamper stamper = new Stamper(Stamper.SizeType.e_relative_scale, 0.9, 0.9))
// set your font and color here if you like
stamper.SetAlignment(Stamper.HorizontalAlignment.e_horizontal_center, Stamper.VerticalAlignment.e_vertical_center);
stamper.StampText(tempPdfDoc, text, new PageSet(1));
// page 1 now has our appearance
// now make annotation and stamp back on the temp page.
stamper.StampPage(tempPdfDoc, tempPage, new PageSet(1));
Annot tempStamp = tempPdfDoc.GetPage(1).GetAnnot(0);
Obj tempAp = tempStamp.GetAppearance();
// now we need to import annotation appearance and resources (font and image) to the target document
// once the using statement ends all the temporary objects will be released
Obj importedAp = doc.GetSDFDoc().ImportObj(tempAp, true);