ID_type tags

unbrickable

Hello,

i want to retreive design_id and bl_id from the database for a few parts in an xml file:
I use the following command :
https://api.brickowl.com/v1/catalog/id_lookup?key=key&id=partnumber&type=Part&id_type=design_id
but i gives back an empty box

partnumber i used : 268558

anyone know what i'm doing wrong, is the wrong value for the id_type ?
Does anyone know what the possible tags are for the optional ID_type command ?

thanks in advance