I am using activescaffold with form override

I find the the select tag value cannot be insert into table

Processing CustomerController#create (for at 2007-09-13
21:22:43) [POST]
Session ID: 1358d30acc2435d9fa2d0242127e0266
Parameters: {“commit”=>“Create”, “billing_address_id”=>“1”,
“action”=>“create”, “controller”=>“customer”, “record”=>{“name”=>“n”,

INSERT INTO customers (name, shipping_address_id,
billing_address_id) VALUES(‘n’, NULL, NULL) [0m

In the parameters line, you could see billing_address_id and

but none of them appear in the insert statement.

I want to write a before_save method to fix this.

I tried
seld.billing_address_id = billing_address_id
self.shipping_address_id = params[record][shipping_address_id]

but none works.

How should I do this?