Pass JSON object to WCF endpoint

Question

I am trying to send a simple (8 item) structure to WCF. I can't seem to get it correct. Any suggestions on where to look for a solution.
Here's the object declaration & call
Thanks
Abbott
function ContentEntryItem(ContentEntryId,
                          ContentType,
                          Date,
                          ProviderId,
                          ProviderName,
                          Title,
                          Tip,
                          LinkId,
                          LinkUrl) {
        this.ContentEntryId = ContentEntryId;
        this.ContentType = ContentType;
        this.Date = Date;
        this.ProviderId = ProviderId;
        this.ProviderName = ProviderName;
        this.Title = Title;
        this.Tip = Tip;
        this.LinkId = LinkId;
        this.LinkUrl = LinkUrl;
}

        function UpdateContent() {
            var today = new Date();
            var contentEntry = new ContentEntryItem(0,
                  "Sermons",
                  today,
                  1,
                   "Peter Piper",
                   "The Time Sermon",
                   "A tip in time",
                   0,
                   "~/sermons/20100212.pdf");
            AddUpdateContentWCFJSON(contentEntry);
        }

        function AddUpdateContentWCFJSON(contentEntryItem) {
            varJType = "POST";
            varJUrl = "Service/JsonContentWcfService.svc/AddUpdateContent";
            varJData = '{"ContentEntryItem": "' + contentEntryItem + '"}';
            varJContentType = "application/json; charset=utf-8";
            varJDataType = "json";
            varJProcessData = true;
            CallJsonService();
        }
        function CallJsonService() {
            $.ajax({
                type: varJType, //GET or POST or PUT or DELETE verb
                url: varJUrl, // Location of the service
                data: varJData, //Data sent to server
                contentType: varJContentType, // content type sent to server
                dataType: varJDataType, //Expected data format from server
                processdata: varJProcessData, //True or False
                success: function(msg) {//On Successfull service call
                    JsonServiceSucceeded(msg);
                },
                error: JsonServiceFailed// When Service call fails
            });
        }