Two options:
Patch the source: https://github.com/jamesarosen/ember-i18n/blob/master/lib/i18n.js#L133 and https://github.com/jamesarosen/ember-i18n/blob/master/lib/i18n.js#L170
Or create your own simple helper:
Ember.Handlebars.registerHelper('i18n', function(key) {
return new Handlebars.SafeString(Ember.I18n.t(key))
});
and then
{{i18n generic.title.edit}}
Hope it helps.