Custom link to add product
problem was that i didn't knew very well how menu hook worked
solution is:

foreach (commerce_product_types() as $type =&gt; $product_type) {
  $items['sell/' . strtr($type, array('_' =&gt; '-'))] = array(
    'title' =&gt; 'Sell !name',
    'title arguments' =&gt; array('!name' =&gt; $product_type['name']),
    'page callback' =&gt; 'commerce_product_ui_product_form_wrapper',
    'page arguments' =&gt; array(commerce_product_new($type)),
    'access callback' =&gt; 'commerce_product_access',
    'access arguments' =&gt; array('create', commerce_product_new($type)),
    'file' =&gt; 'includes/commerce_product_ui.products.inc',
    'file path' =&gt; $commerce_product_bp,
  );
}


didn't have to apend the path to function names, thought those where called by path for some reason..