Use certificates for signing

To sign the data with X.509 certificates, you need to employ TElXMLKeyInfoX509Data class. All you need to do is

1. Create an instance of TElXMLKeyInfoX509Data class.
2. Load the X.509 certificate to the instance of TElX509Certificate class. Note, that the certificate MUST contain a private key.
3. Set the loaded certificate to Certificate property of TElXMLKeyInfoX509Data class. Note, that the original object is set. No copy is made.
4. Set KeyData property of TElXMLSigner to the instance of TElXMLKeyInfoX509Data class which contains the certificate.