Create repeating elements in xml document

Good day,

I have a problem with a project I am busy with. I am creating an XML document from a predefined schema. I am able to this with no problem for one level using this method:

{

                XmlSerializerNamespaces ns = new XmlSerializerNamespaces();

                XmlSerializer serializer = new XmlSerializer(typeof(UKFATCASubmissionFIReport));
                TextWriter writer = new StreamWriter(destinationPath);
                UKFATCASubmissionFIReport fatcaSub = new UKFATCASubmissionFIReport();
                fatcaSub.SchemaVersion = schemaVersion;

                //Initialize classes and objects
                #region classes and objects

                AccountDataType accountData = new AccountDataType();
                AccountHolderCodeType accountHolderType = new AccountHolderCodeType();
                MessageDataType messageData = new MessageDataType();
                MonetaryType moneyType = new MonetaryType();
                SubmissionType submissionData = new SubmissionType();
                FIReturnActionType fireturnActionData = new FIReturnActionType();
                AccountActionType accountActionData = new AccountActionType();
                TINCodeType tinCode = new TINCodeType();
                HolderTaxInfoType holderInfo = new HolderTaxInfoType();
                //PaymentDataType paymentData = paymentDetails();


                #endregion


                //Monetary type
                moneyType.Value = moneyTypeValue;
                moneyType.currCode = currCode_Type.GBP;

                //Create message data
                messageData.FATCAUserId = FatcaUserID;
                messageData.XMLTimeStamp = timeStamp;
                messageData.MessageCategory = MessageType.NewSubmission;
                fatcaSub.MessageData = messageData;

                //Create submission data object
                submissionData.ReportingPeriod = reportingPeriod;
                submissionData.Item = messageRef;
                fatcaSub.Item = submissionData;

                //FI Return Action

                fireturnActionData.Action = ActionType.New;
                fireturnActionData.FIReturnRef = returnRef;

                //FIReturnActionType[] fireturnItems = new FIReturnActionType[] { fireturnActionData };
                //TIN Code Type
                tinCode.TINCountryCode = countryCode;
                tinCode.Value = tinCodeValue;
                tinCode.TINCountryCodeSpecified = itemSpecified;

                //TIN Information
                holderInfo.ReportableJurisdiction = countryCode;
                holderInfo.TIN = holderTIN;
                holderInfo.TINCode = tinCode;

                //ContactPersonInformation contactInfo = ContactInformation(holderInfo);
                //Contact address
                ContactAddressType contactAddress = new ContactAddressType();
                contactAddress.StreetName = streetName;
                contactAddress.City = contactCity;
                contactAddress.CountryCode = holderInfo.ReportableJurisdiction;

                //Person Details
                ContactPersonInformation contactInfo = new ContactPersonInformation();
                contactInfo.FirstName = firstName;
                contactInfo.LastName = lastName;
                contactInfo.Address = contactAddress;
                contactInfo.HolderTaxInfo = holderInfo;
                contactInfo.BirthDateSpecified = itemSpecified;
                contactInfo.BirthDate = dateOfBirth;

                PaymentMonetaryType paymentMonetary = new PaymentMonetaryType();
                paymentMonetary.currCode = currCode_Type.GBP;
                paymentMonetary.Value = paymentValue;

                //Payment data object
                PaymentDataType paymentData = new PaymentDataType();
                paymentData.PaymentCode = PaymentCodeType.Item20;
                paymentData.PaymentAmount = paymentMonetary;
                //return paymentData;

                //Account action
                accountActionData.AccountRef = accountRef;
                accountActionData.Action = ActionType.New;

                //Account information array
                //AccountData(paymentData, contactInfo, accountActionData, accountData, accountHolderType);

                object[] accountItems = new object[] { accountActionData, accountNumber, paymentData, accountHolderType, contactInfo };
                accountData.Items = accountItems;

                ItemsChoiceType[] accountFieldNames = new ItemsChoiceType[] { ItemsChoiceType.AccountAction, ItemsChoiceType.AccountNumber, ItemsChoiceType.PaymentData, ItemsChoiceType.AccountHolderType, ItemsChoiceType.Person };
                accountData.ItemsElementName = accountFieldNames;

                //Financial Information Return main array
                //FIReturn(submissionData, fireturnActionData, accountData);

                FIReturnType fireturn = new FIReturnType();
                object[] fiItems = new object[] { fireturnActionData, fiRegisterID, dueDilligenceInd, thresholdInd, accountData };
                fireturn.Items = fiItems;

                ItemsChoiceType1[] fiFieldnames = new ItemsChoiceType1[] { ItemsChoiceType1.FIReturnAction, ItemsChoiceType1.FIRegisterId, ItemsChoiceType1.DueDiligenceInd, ItemsChoiceType1.ThresholdInd, ItemsChoiceType1.AccountData };
                fireturn.ItemsElementName = fiFieldnames;

                FIReturnType[] fiData = new FIReturnType[] { fireturn  };
                //Map FI return data to submissionData
                submissionData.FIReturn = fiData;

                //Serialize the submission close the TextWriter

                serializer.Serialize(writer, fatcaSub);

                writer.Close();

                Process.Visible = false;
                MessageBox.Show("Processing Complete!", "Complete", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1);
                Close();

            }

The problem is that I would like fireturn to appear in the document more than once from a dataset. If I changed my code to this:

FIReturnType[] fiData = new FIReturnType[] { fireturn, fireturn, fireturn  };
                //Map FI return data to submissionData
                submissionData.FIReturn = fiData;