How to set GL codes on a Sales Invoice in Microsoft Dynamics GP?

Question

I'm using Microsoft Dynamics GP 2015. We have a C# .Net project to create a sales invoice through web services. Accounting has the following request: "We would like to code the revenue for {an item} to GL code xx-xx-xxxx." Looking at the code for creating a sales invoice, I don't see anywhere to set a GL code. I suggested GL codes might be set on an item in GP, but was told to "see if the distribution or account codes can be set at creation time." Is there anyway to set the GL code on a sales invoice? If so, what's the code for setting a GL code?

Here's the code I'm modifiying:

private string createGPSalesInvoice(ItemReceived itemsReceived, DateTime salesOrderDate)
    {
        CompanyKey companyKey;
        companyKey = new CompanyKey();

        Context context;
        SalesInvoice salesInvoice;
        SalesDocumentTypeKey salesInvoiceType;

        CustomerKey customerKey;
        customerKey = new CustomerKey();

        BatchKey batchKey;
        SalesInvoiceLine salesInvoiceLine;
        ItemKey invoiceItem;
        Quantity invoiceCount;

        Policy salesInvoiceCreatePolicy;
        salesInvoiceCreatePolicy = new Policy();

        string salesInvoiceNumber = "";

        try
        {
            // Create an instance of the service
            DynamicsGPClient wsDynamicsGP = new DynamicsGPClient();

            // Create a context with which to call the service
            context = new Context();

            // Specify which company to use (sample company)

            companyKey.Id = xxx;

            // Set up the context object
            context.OrganizationKey = (OrganizationKey)companyKey;

            // Create a sales invoice object
            salesInvoice = new SalesInvoice();

            // Create a sales document type key for the sales invoice
            salesInvoiceType = new SalesDocumentTypeKey();
            salesInvoiceType.Type = SalesDocumentType.Invoice;

            // Populate the document type key for the sales invoice
            salesInvoice.DocumentTypeKey = salesInvoiceType;

            // Create a customer key
            customerKey.Id = xxx;

            // Set the customer key property of the sales invoice
            salesInvoice.CustomerKey = customerKey;

            salesInvoice.PostedDate = parms.endDate;

            // Create a batch key
            batchKey = new BatchKey();
            batchKey.Id = xxx;

            // Set the batch key property of the sales invoice object
            salesInvoice.BatchKey = batchKey;

            // Create a sales invoice line to specify the invoiced item
            salesInvoiceLine = new SalesInvoiceLine();

            // Create an item key
            invoiceItem = new ItemKey();
            invoiceItem.Id = itemsReceived.GPPartNumber;

            // Set the item key property of the sales invoice line object
            salesInvoiceLine.ItemKey = invoiceItem;

            // Create a sales invoice quatity object
            invoiceCount = new Quantity();
            invoiceCount.Value = itemsReceived.Quantity;


            // Set the quantity of the sales invoice line object
            salesInvoiceLine.Quantity = invoiceCount;

            MoneyAmount unitCost = new MoneyAmount()
            {
                Value = itemsReceived.CostEach
            };

            salesInvoiceLine.UnitPrice = unitCost;

            // Create an array of sales invoice lines
            // Initialize the array with the sales invoice line object
            SalesInvoiceLine[] invoiceLines = { salesInvoiceLine };

            // Add the sales invoice line array to the sales line object
            salesInvoice.Lines = invoiceLines;

            try
            {
                // Get the create policy for the sales invoice object
                salesInvoiceCreatePolicy = wsDynamicsGP.GetPolicyByOperation("CreateSalesInvoice", context);
            }
            catch (Exception ex)
            {
                throw ex;
            }

            try
            {
                // Create the sales invoice
                wsDynamicsGP.CreateSalesInvoice(salesInvoice, context, salesInvoiceCreatePolicy);
            }
            catch (Exception ex)
            {
                throw ex;
            }

            //CREATE A RESTRICION OF THE BATCH ID TO FIND THE SALES DOC JUST CREATED
            LikeRestrictionOfstring batchKeyRestriction = new LikeRestrictionOfstring();
            batchKeyRestriction.EqualValue = batchKey.Id;

            //CREATE SEARCH CRITERIA
            SalesDocumentCriteria salesDocumentCriteria = new SalesDocumentCriteria();
            salesDocumentCriteria.BatchId = batchKeyRestriction;

            try
            {
                SalesDocumentSummary[] salesDocumentSummary = wsDynamicsGP.GetSalesDocumentList(salesDocumentCriteria, context);
                salesInvoiceNumber = salesDocumentSummary.FirstOrDefault().Key.Id;
            }
            catch (Exception ex)
            {
                throw ex;
            }

            // Close the service
            if (wsDynamicsGP.State != CommunicationState.Faulted)
            {
                wsDynamicsGP.Close();
            }

            return salesInvoiceNumber;
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }