Not Saving my Bill to location when create sales order

I have set up a customer relationship. Customer A related to customer B. When create a sales order i selected the customer B in the Bill to customer for Customer A. In the form it picked customer B and i saved. i query back the sales order it shoes the customer A. see the screenshot

Is there any profile i need to set  to make it effective.

My set up for Customer Relationships is Related Customer.