Retriving Entity including RelatedEntity using OrganizationService and without using SDK

At Present I am getting  orders with following code, Now I want to get even related entities like products with salesorder. Can any one please suggest me code block for retrieving related entity with salesorder.

I dont want to use any sdk dlls here. only Organization service reference.

                OrganizationService.ColumnSet cset = new ColumnSet();
                cset.Columns = new string[] { "new_orderid", "salesorderid", "pricelevelid", "transactioncurrencyid", "customerid" };
                QueryExpression salesorderQuery = new QueryExpression
                {
                    EntityName = "salesorder",
                    ColumnSet = cset,
                    Criteria = new FilterExpression
                    {

                    },
                  // LinkEntities= new LinkEntity[]{relatedEntity};
                };

                Entity[] salesorder = client.RetrieveMultiple(salesorderQuery).Entities;

Thanks Regards Prashanth Kamasamudram Even the least work done for others awakens the power within; even thinking the least good of others gradually instills into the heart the strength of a lion.