JavaFX 2.2: How to set SimpleBooleanProperty value to null?

JavaFX 2.2: How to set SimpleBooleanProperty value to null?

If I do so:
BooleanProperty b = new SimpleBooleanProperty();
b.setValue(null);
System.out.println(b.getValue());
I recieve output:
false
How to set SimpleBooleanProperty value to null? Set SimpleBooleanProperty
to null (BooleanProperty b = null;) is bad idea, because I will use
binding.