vTiger .net c#销售订单失败- MANDATORY_FIELDS_MISSING " message ":"

在VTiger 6.15.7.6版本中创建销售订单时抛出异常

发送以下实体用于销售订单创建

            VTigerListItem[] arrListItem = new VTigerListItem[1];
            arrListItem[0] = new VTigerListItem() { productid = "25x405",     listprice = "468.25", quantity = "1" };
            VTigerSalesOrder[] arrListItem1 = new VTigerSalesOrder[1];                
            arrListItem1[0] = new VTigerSalesOrder()
            {
                start_period = "2015-01-01",
                end_period = "2015-01-01",
                subject = "Testing",
                contact_id = "4x680",
                sostatus = SoStatus.Created,
                account_id = "3x679",
                assigned_user_id = "19x11",
                bill_street = "test bill street",
                invoicestatus = Invoicestatus.Created,
                productid = "25x405",                   
                cf_1121 = "RDMS",
                createdtime = "2015-01-01",
                modifiedtime = "2015-01-01",
                LineItems = arrListItem
            };  
            var desc = vtigerApi.Create(arrListItem1[0]);