How to overwrite primary_key in Kohana 3?

Question

ORM

Available model

class Model_Order extends ORM {

  protected $_table_name = 'orders';
  protected $_primary_key = 'number';
.......................
}

Since the number field is the Primary Key, I myself cannot change this field using the write method using

ORM::factory('order')->values(array(
'number' => 123456
))->create();

This field is set to 0, no matter how hard I try.
Also in the model there is an ID with autoincrement, which was the Primary Key before, but according to the structure, it is necessary that number be the Primary Key.