Why entity autoloading doesn't work? I'm trying to set up entity autoloading using hook_menu like this:

    $menu['e-shop/produkt/detail/%commerce_datasheet'] = array(
    'title' =&gt; t('Products'),
    'page_callback' =&gt; 'commerce_products_datasheet_detail',
    'page_arguments' =&gt; array(3),
    'access callback' =&gt; TRUE,
     );

function commerce_datasheet_load($datasheet_id) {
  return entity_load_single('commerce_datasheet',$datasheet_id);
}

function commerce_products_datasheet_detail($entity, $view_mode='full') {
    dpm($entity); 
}


dpm() function doesn't return anything, so I assume, that $entity is empty.

I am using latest versions on Drupal 7 and Entity API module.
It was my mistake. I was using another module, which provided page callback with higher priority. For the next time - it's advisable to install devel module and go to devel/menu/item?path=&lt;uri&gt; where used page callback can be clearly seen.