Alter exposed filter textfield to become autocomplete

I would like to alter an exposed view filter (of a node title) so it becomes an autocomplete. In my module I have something like the following code:

function my_module_form_views_exposed_form_alter(&$form, $form_state) {
  if(isset($form_state['view']->name) && $form_state['view']->name == 'some_form') {
    $form['title']['#autocomplete_path'] = 'path/to/custom/autocomplete';
  }
}

This does not seem to be doing anything. The ['#autocomplete_path] attribute is present in the $form array. I looked at how the views handler for taxonomy attaches autocomplete and it seemed to be attaching #autocomplete_path to a textfield too. Any documentation on how to go about this would be much appreciated.