Restify, Node.js urlencoding for routes processing

I have a route like this -

server.get({
    url : '/reguser/:useremail',
    name : 'pre-register-user'
    }, function(req, res, next) {
        return next();
    }, function sendResult(req, res, next) {
        var user = { 'email' : req.params.useremail }
      // Create a new user on the DB
      res.contentType = 'application/json';
      // rest of the processing.
}

Works if it gets called with /prereg/someone%40someemail.com. But if it gets /prereg/someone@someemail.com it does not process at all. I am using Nginx in the front and rewrite in it replaces the %40 with @ even though the web-page is sending urlencoded string with %40.

Any way out of this?