How do I observe properties in an Ember route template?

I have a route that sometimes shows a dialog. My idea for this was to create a component like this:

{{modal-dialog visible=dialogVisible contents=dialogContents}}

The route would, as needed, set the dialogVisible and dialogContents properties, and the template would pass these properties on to the modal-dialog component accordingly, so the dialog would appear and show the correct content.

But that doesn't work. Templates observe routes' models, not their properties. How can I get access to route properties in my template?