How to add Custom Alternative Names in Bouncy Castle

[smartkodian]

I have this code to generate CSR ECDSA and it works fine, but I want to add these Alternative names to the CSR but don't know how to do it:

This is the code I am using in C# which can generate CSR and it works:

static  AsymmetricCipherKeyPair GeneratePkcs8Pkcs10(string countryIso2Characters, string state, string city, string companyName, string division, string domainName, string email, RootLenght rootLength)
{
	string csr = null;


	var curve = ECNamedCurveTable.GetByName("secp256k1");
	var domainParams = new ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H, curve.GetSeed());

	var secureRandom = new SecureRandom();
	var keyParams = new ECKeyGenerationParameters(domainParams, secureRandom);

	var generator = new ECKeyPairGenerator("ECDSA");

	generator.Init(keyParams);
	AsymmetricCipherKeyPair Pair = generator.GenerateKeyPair();
	var cGenerator = new X509V3CertificateGenerator();
	IDictionary attrs = new Hashtable();

	attrs.Add(X509Name.C, countryIso2Characters);
	attrs.Add(X509Name.L, city);
	attrs.Add(X509Name.ST, state);
	attrs.Add(X509Name.O, companyName);
	if (division != null)
	{
		attrs.Add(X509Name.OU, division);
	}
	attrs.Add(X509Name.CN, domainName);
	if (email != null)
	{
		attrs.Add(X509Name.EmailAddress, email);
	}

	var subject = new X509Name(new ArrayList(attrs.Keys), attrs);

	var pkcs10CertificationRequest = new Pkcs10CertificationRequest(X9ObjectIdentifiers.ECDsaWithSha256.Id, subject, Pair.Public, null, Pair.Private);
	csr = Convert.ToBase64String(pkcs10CertificationRequest.GetEncoded());

	var privateKey = Pair.Private as ECPrivateKeyParameters;

	var pkInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(Pair.Private);

	string privateKeyB64 = Convert.ToBase64String(pkInfo.GetDerEncoded());

	Console.WriteLine($"Private key: {privateKeyB64}");

	Console.WriteLine("-----BEGIN CERTIFICATE REQUEST-----");
	Console.WriteLine(SpliceText(csr, 64));
	Console.WriteLine("-----END CERTIFICATE REQUEST-----");
	ertificate Signing Request succesfully generated.");

	Console.ReadKey();
	return Pair;
}

the Alternate Names want to add SN=334623324234325, UID=310122393500003, title=0000, registeredAddress=Sample E, businessCategory=Sample Bussiness and also add extension: [req_ext] certificateTemplateName = ASN1:PRINTABLESTRING:ZATCA-Code-Signing subjectAltName = dirName:alt_names