Submit DS.Model event in controller

I have the following controller :

export default Controller.extend({
  /* model is an array of Posts */

  didDeletePost(post) {
    /* PROBLEM HERE : post is an InternalModel */
    this.get('model').removeObject(post);
  },

  actions: {
    markPostForDelete(post) {
      post.markForDelete(); /* starts a timer */
      post.one('didDelete', this, this.didDeletePost);
    },
    clearMarkPostForDelete(post) {
      post.clearMarkForDelete(); /* cancel a timer */
      post.off('didDelete', this, this.didDeletePost);
    }
  }
});

But remove the post in didDeletePost does not work because the post argument is the InternalModel, not the DS.Model.

How can I achieve this ?

As it does not seem to be easy to do it like this, I guess there should be a better way to implement this kind of timer ?