Ok i finally find the file, and manage to add the categories.. here it is if it can help someone

file:

tb_themes/pavilion/catalog/plugin/ProductPlugin.php 

find:

foreach ($products as &$product) {

add right afterwards:

// add categories and attribute variables 
$querycats = $this->getOcModel('catalog/product')->getCategories( $product['product_id']);
$categories = array();
foreach( $querycats as $item ) {
  $categ = $this->getOcModel('catalog/category')->getCategory($item['category_id']);
  $catinfo['id'] = $item['category_id'];
  $catinfo['name'] = $categ['name'];
  $catinfo['href'] = $this->manager->getOcUrl()->link('product/category', 'path=' . $item['category_id']);
  $categories[] = $catinfo;
}
$product['attribute_groups']   = $this->getOcModel('catalog/product')->getProductAttributes( $product['product_id']);
$product['categories'] = $categories;

You can then use those variables in the tpl file catalog/view/theme/pavilion/template/tb/widget/_list_products.tpl

have fun