NHibernate中的映射问题

public class Customer
{
    public virtual int CustomerID { get; protected set; }
    public virtual string AccountNumber { get; protected set; }
    public virtual string CustomerType { get; set; }
    public virtual int TerritoryID { get; set; }
    public virtual SalesTerritory Territory { get; protected set; }
}

使用Fluent NHibernate绘制地图如下:

    public class CustomerMapper : ClassMap<Customer>
{
    private const string schema = "Sales";
    public CustomerMapper()
    {
        SchemaIs(schema);
        Id(x => x.CustomerID);
        Map(x => x.CustomerType).WithLengthOf(1).Not.Nullable();
        Map(x => x.TerritoryID).Not.Nullable();

        Map(x => x.AccountNumber).ReadOnly()
            .Update(false)
            .Insert(false)
            .Generated(Generated.Insert);

        References<SalesTerritory>(x => x.Territory).TheColumnNameIs(ReflectionHelper.GetProperty<Customer>(x => x.TerritoryID).Name).LazyLoad().Update(false).Insert(false);
    }
}

更新 生成的映射文件中属性的属性。

<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="true" assembly="Model" namespace="Model" schema="Sales">
    <class name="Customer" table="`Customer`" xmlns="urn:nhibernate-mapping-2.2">
        <id name="CustomerID" column="CustomerID" type="Int32">
            <generator class="identity" />
        </id>
        <property name="AccountNumber" column="AccountNumber" insert="false" update="false" generated="insert" length="100" type="String">
            <column name="AccountNumber" />
        </property>
        <property name="TerritoryID" column="TerritoryID" not-null="true" type="Int32">
            <column name="TerritoryID" />
        </property>
        <property name="CustomerType" column="CustomerType" not-null="true" length="1" type="String">
            <column name="CustomerType" />
        </property>
        <many-to-one lazy="proxy" update="false" insert="false" name="Territory" column="TerritoryID" />
    </class>
</hibernate-mapping>

我的问题是,当一个新的客户实例保存到数据库中时,客户实例的Territory属性为null。
如何使此属性在保存到数据库后包含正确的值? 生成
或者我的客户类有什么问题吗?
提前谢谢。