Entity Framework map struct/complex type without model properties

I have a 'model struct' which is internally a string, but is being used to somewhat similiar to a GUID.

public struct Token {

    private string _value;

    private Token(Guid uuid) {
        _value = Token.FromGuid(uuid);
    }

    public static Token FromGuid(Guid uuid) {
        // perform 'transformation'
        // stuff
        // return...
    }

    // other static methods to create a token...

}

How can I map this entity using Entity Framework 6 Code First? I'm aware that structs are not supported, but a complex type also doesn't seem applicable since the class doesn't contain any properties.