Finally i had create a taxonomy with name manufacturers and an attribute with the same name. This may caused a confict (i didn’t find out more!). So i create an attribute with name brands and i use this for my custom query.
Finally i had create a taxonomy with name manufacturers and an attribute with the same name. This may caused a confict (i didn’t find out more!). So i create an attribute with name brands and i use this for my custom query.