Sigh... No matter which mapping tool one use, if one cannot get its modelization right in the first place, it doesn't matter, isn't it?
More to the point, Manager should not be a subclass of Employe. An Employe is simply a contact. A Manager is a role. An Employe could be a Janitor also. Are you going to modelize that by subclassing Employe? Duh. Looking forward to see how you modelize an Employe with multiple roles.
I assume that's what multiple inheritance is for: bogus object model... Oh well...