PriceListService throws exception CustAccount is not a field in data source SalesPrice

            PriceListServiceClient client = new PriceListServiceClient();
            CriteriaElement[] criteriaElement = new CriteriaElement[1];
            criteriaElement[0] = new CriteriaElement();
            criteriaElement[0].DataSourceName = "SalesPrice";
            criteriaElement[0].FieldName = "CustAccount";
            criteriaElement[0].Operator = Operator.Equal;
            criteriaElement[0].Value1 = "9100";
            QueryCriteria queryCriteria = new QueryCriteria();
            queryCriteria.CriteriaElement = criteriaElement;
            CallContext callContext = new CallContext();

            var found = client.find(callContext, queryCriteria);
            client.Close();