passport: Passport.js does not work with cookieSession (Express.js)

I’m using Passport to log in with Facebook or Twitter into my service. Since MemoryStore is not intended for production and I’m not going to store much information into the session, I wanted to use cookieSession, but it doesn’t work:

app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.cookieParser());
app.use(express.cookieSession({ secret: 'keyboard cat', cookie: {maxAge: 60 * 60} }));
app.use(passport.initialize());
app.use(passport.session());
app.use(app.router);

It works as expected if I repace cookieSession() with session():

app.use(express.session({ secret: 'keyboard cat' }));