Sending estimate amount parameter to QuickBooks desktop on invoice creation using SDK in .NET 8

Question

I have service in C# to create invoices in QuickBooks Desktop using QB SDK and QBFC16Lib library.

That part of it's code of generation IMsgSetRequest:

IMsgSetRequest requestMsgSet = qbSession.CreateMsgSetRequest("US", 16, 0);
requestMsgSet.Attributes.OnError = ENRqOnError.roeContinue;

IInvoiceAdd invoiceAddRq = requestMsgSet.AppendInvoiceAddRq();
invoiceAddRq.CustomerRef.FullName.SetValue(customerRefFullName);
invoiceAddRq.TxnDate.SetValue(invoice.CreatedDate);
invoiceAddRq.DueDate.SetValue(invoice.DueDate);
invoiceAddRq.TemplateRef.FullName.SetValue("My Progress Invoice");

foreach (var scheduled in invoice.Scheduled)
{
    IORInvoiceLineAdd orderLine = invoiceAddRq.ORInvoiceLineAddList.Append();
    orderLine.InvoiceLineAdd.ItemRef.FullName.SetValue(itemName);
    orderLine.InvoiceLineAdd.Amount.SetValue((double)scheduled.WorkThisPeriod);
    orderLine.InvoiceLineAdd.Desc.SetValue(scheduled.Description);
}

I have no idea how to add "Estimate Amount" parameter to orderLine or invoiceAddRq.

These are screenshots of the parameter that I mean from QB Desktop:

Maybe someone has an idea how I can pass in this parameter?