如何告诉nhibernate加载一个组件不为空,即使它的所有属性都为空?

我有一个包含日期时间的日期类?类(帮助模拟日期时间。现在,我们的域等)。

日期类类类只有一个受保护的属性:datetime?日期

public class Date
{
    protected DateTime? date;
}

// mapping in hbm
<component name="CompletedOn">
  <property column="StartedOn" name="date" access="field" not-null="false" />
</component>

从NHibernate文件:

Like all value types, components do not support shared references. The null value semantics of a component are ad hoc. When reloading the containing object, NHibernate will assume that if all component columns are null, then the entire component is null. This should be okay for most purposes.

我能改变这种行为吗?我希望我的日期类被实例化,即使日期为空。

谢谢,