title: iTextSharp z-index
body: <p>I'm using itextSharp to add anotations in a pdf document.  </p>
  
  <p>I have a pdf document that already contains an image saved in it, it's a stamp.  </p>
  
  <p>So I draw some stroke on this pdf in the stamp and everything is fine when I draw them in my WPF but when I send the pdf by email using iTextSharp for the conversion the line I drawed is now below the stamp.</p>
  
  <p>How I can solve this problem ?</p>
  
  <p>Thank you</p>