Add phone number or any other field to address

Hi,
I would very much like to add phonenumber to the addressbook.
I want it in the Addressbook module because when I add it next to the Addressbook a lot of commerce functionality doesn't look nice.
For instance the "Choose Billing address the same as Shipping Address".
This set underneath the Addressbook field and when I add phonenumber as normal field it set underneath the Choose selectbox.

Thanks a lot in advance for considering to add the possibility to add fields to the Addressbook.

greetings, Martijn