Entity Framework Enable for subclass navigation properties

Question

In the Entity Framework, it's easy to include navigation properties using Include, for example efContext.MyObjects.Where(mo => mo.prop == "value").Include(mo => mo.nav). My problem is that I have an application where there is inheritance, and I would like the subclasses to be included in my query also include some of their navigation properties (but not all entities will be a subclass). Is there any way to do this?

I tried using line overloading in Include, but this causes the exception to complain about the base class not declaring such a navigation property.