private static X509Certificate CreateDotNetCertificate(Org.BouncyCastle.X509.X509Certificate certificate, AsymmetricCipherKeyPair keyPair)
{
   var store = new Pkcs12Store();
   string friendlyName = certificate.SubjectDN.ToString();
   var certificateEntry = new X509CertificateEntry(certificate);
   store.SetCertificateEntry(friendlyName, certificateEntry);
   store.SetKeyEntry(friendlyName, new AsymmetricKeyEntry(keyPair.Private), new[] { certificateEntry });

   var stream = new MemoryStream();
   var password = "a password";
   store.Save(stream, password.ToCharArray(), new SecureRandom(randomGenerator));

   return new X509Certificate2(stream.ToArray(), password, X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.Exportable);
}