Can I bind a WPF control to a field's property?

Because I needed to split some functionality between classes, I've arrived at the following situation

xaml code

<CheckBox IsChecked="{Binding MyObjectField.MyBoolean}"  />

view model

...
public MyInternalObject MyObjectField;
...

MyObject class

public class MyInternalObject {
    ...
    public bool MyBoolean { get; set; }
    ...
}

It does not work unless I replicate the MyBoolean property in the View Model class.

public bool MyBoolean 
{ 
    get { return MyInternalObject.MyBoolean; }
    set { MyInternalObject.MyBoolean=value; }
}

Does anyone have an idea?