The only way I've figured out how to do this is to have two properties for my class. One as the boolean for the programming API which is not included in the mapping. It's getter and setter reference a private char variable which is Y/N. I then have another protected property which is included in the hibernate mapping and it's getters and setters reference the private char variable directly.
EDIT: As has been pointed out there are other solutions that are directly built into Hibernate. I'm leaving this answer because it can work in situations where you're working with a legacy field that doesn't play nice with the built in options. On top of that there are no serious negative consequences to this approach.