使用WCF从类库中公开对象

I'm using a class library that exposes a few objects. These objects have a couple of properties that hold data my clients need. I'd like to create a WCF service that returns the objects to my clients but I cannot update the class library in order to add the DataContract and DataMember attributes. What is the easiest way of exposing these objects?I'm using a class library that exposes a few ob