Embedding an EmberJS application into an existing page

How would I embed the EmberJS app in an existing app? I would like to open the EmberJS app as a modal, on top of the existing app. Two main questions 1.routing; how would I open the emberJS app without interfering with routing? Not sure if this will do the job:

App = Ember.Application.create({
      rootElement: '#app'
});

2.Closing the modal window to return to existing app?

Thank you for your comments