title: Sign PDF with already created CMS Signature c#
body: <p>I want to sign a PDF by an external service, that asks for a PDF in BASE64 Formate and the response contains a CMS Signature for this PDF. </p>
  
  <p>How can I add this Signature to the PDF?</p>
  
  <p>I checked the CMS via <a href="https://lapo.it/asn1js/#" rel="nofollow noreferrer">https://lapo.it/asn1js/#</a> and it is valid. </p>