function crypto_get_sign_message(...)
...
begin
   ...
          SetLength(MessageArray, 1);
          SetLength(MessageSize, 1);
          SetLength(MessageCert, 1);
          MessageArray[0] := Pointer(str);
          MessageSize[0] := strlen(str);
          FillChar(SigParams, SizeOf(CRYPT_SIGN_MESSAGE_PARA ), 0);
          SigParams.cbSize := SizeOF(CRYPT_SIGN_MESSAGE_PARA);
          SigParams.dwMsgEncodingType := X509_ASN_ENCODING or PKCS_7_ASN_ENCODING;
          SigParams.pSigningCert := pContext;
          SigParams.HashAlgorithm.pszObjId := szOID_CP_GOST_R3411;
          SigParams.cMsgCert := 0;
          if CryptSignMessage(@SigParams, True, 1, Pointer(MessageArray), Pointer(MessageSize), nil, signSize) then 
            begin
              data := AllocMem(signSize);
              try
                if CryptSignMessage(@SigParams, True, 1, Pointer(MessageArray), Pointer(MessageSize), data, signSize) then
                    Result := crypto_binary_to_string(data, signSize);
               finally
                  FreeMem(data);
               end;
            end;
   ...
end;

{
  ...
      SmevSignedXml signedXml = new SmevSignedXml(doc);
      signedXml.SigningKey = cert.PrivateKey;
      ...
      reference.DigestMethod = CryptoPro.Sharpei.Xml.CPSignedXml.XmlDsigGost3411UrlObsolete;
      XmlDsigExcC14NTransform c14 = new XmlDsigExcC14NTransform();
      reference.AddTransform(c14);
      signedXml.AddReference(reference);

      signedXml.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NTransformUrl;
      signedXml.SignedInfo.SignatureMethod = CryptoPro.Sharpei.Xml.CPSignedXml.XmlDsigGost3410UrlObsolete;
      signedXml.ComputeSignature();
      ...
}