How use the command POST new objectdata in Eb by webservice

using (HttpClientHandler ch = new HttpClientHandler() { UseDefaultCredentials = true })

                using (HttpClient client = new HttpClient(ch))

                {

                    ObjectData od = new ObjectData();

                    od.CoverId = 113;

                    od.Attributes = new LinkList<AttributeData>();

                    od.Attributes.Items = new List<AttributeData>();

                    od.Attributes.Items.Add(new AttributeData() { AttributeId = 5, AttributeValue = new AttributeValue() {Value = "Test web service" } });



                    JavaScriptSerializer jss = new JavaScriptSerializer();

                    string presq = jss.Serialize(od);

                    StringContent spresq = new StringContent(presq);



                    using (HttpResponseMessage response = await client.PostAsync("http://jco-nb:8734/api/rs/v1/EB671_BRM/objects/00000000-0000-0000-0000-00000137E0C4", spresq))

                    using (HttpContent content = response.Content)

                    {

                        // ... Read the string.



                        resp = await content.ReadAsStringAsync();

                    }

                }