multiple variable in get request of express

I got a problem on my express server

app.get('/callback/:nation/:username/?:permalink', function(req, res)
            {
                nationurl = req.params.nation;
                username = req.params.username;
                storypermalink = req.params.permalink;


                console.log("nation: "+nation);
                console.log("username: "+username);
                console.log("permalink: "+permalink);
            });

Beacause of the /?: it split the username and doesn't give my permalink :

nation: poneyclub
username: j
permalink: hondoe

Anybody have an idea ?