Adding a Customer object to a database from a SelectOneMenu - jsf

Question

I am trying to create a new order by selecting a customer name from a SelectOneMenu. I am getting a Conversion error setting value for 'null Converter'.
Order.java
#Entity
#Table(name = "order")
public class Order
{
#Id
#Column(name = "ORDER_ID", nullable = false)
#GeneratedValue(strategy = GenerationType.AUTO)
private long orderId;
#JoinColumn(name = "PRODUCT_ID", referencedColumnName = "PRODUCT_ID")
private Product product;
#Column(name = "QUANTITY")
private int quantity;
#Temporal(TemporalType.TIMESTAMP)
#Column(name = "ORDER_DATE")
private Date orderDate;
#ManyToOne(optional = false)
#JoinColumn(name = "CUSTOMER_ID", referencedColumnName = "CUSTOMER_ID")
private Customer customer;
// Getters & Setters
}
newOrder.xhtml
<h:outputLabel value="Customer: "/>
<h:selectOneMenu id="customer" value="#{solController.order.customer}" >
<f:selectItem itemLabel="" itemDisabled="true"/>
<f:selectItems value="#{solController.customerList}" var="customer" id="customerID" itemLabel="#{customer.customerName}" itemValue="#{customer.customerId}" />
</h:selectOneMenu>
SolController.java
#ManagedBean(name = "solController")
#SessionScoped
public class SolController implements Serializable
{
#EJB
private SolEJB solEJB;
private Order order = new Order();
private List<Order> orderList = new ArrayList<Order>();
public String doCreateOrder()
{
order = solEJB.createOrder(order);
orderList = solEJB.findOrders();
return "listOrders.xhtml";
}
// Getters & Setters
}
SolEJB.java
#Stateless
public class SolEJB
{
#PersistenceContext(unitName = "myPU")
private EntityManager em;
public Order createOrder(Order order)
{
em.persist(order);
return order;
}
}