Asking help - retrieve third-party name of Sales Order Contact

Using my Dolibarr CRM/SRM Modules
1

Not a programmer, I am trying my best to customise my Dolibarr.

In case that Customers have different billing and shipping names / addresses (Billing To / Shipping To), I have to identify these different recipient names / addresses. However, I didn’t find a sales order template to indicate all the information, although I specified the billing (invoice) and shipping contacts, as well as Customer’s representative for order follow-up.

Therefore, I tried to add complementary attributes to Sales Order, to fetch these billing / shipping contacts and their respective Third-Party names. For the computed field, I have tried the follows:

  1. $object->getIdContact(‘external’, ‘BILLING’)[0] and $object->getIdContact(‘external’, ‘SHIPPING’)[0], which can fetch the billing and shipping contact id respectively.

  2. Then I tried the formula below to fetch the fk_soc (contact’s Third Party name), which does not work at all.
    a) (($reloadcontact = new Contact($db)) && ($reloadcontact->fetch($object->getIdContact(‘external’, ‘SHIPPING’)[0])>0)) ? $reloadcontact->fk_soc: ‘-1’
    b) (($reloadcontact = new Contact($db)) && ($reloadcontact->fetch_contact($object->getIdContact(‘external’, ‘SHIPPING’)[0])>0)) ? $reloadcontact->fk_soc: ‘-1’
    After trying differrent ways, it seems to me that $reloadcontact = new Contact($db) may be wrong. However, I don’t know how to resolve it. Can anyone help me?

  3. I already tried the formula below to fetch the Third-Party name, which was working If $id is a specified value:
    (($reloadSoc= new Societe($db))&&($reloadSoc->fetch($id)>0))?$reloadcontact->nom:’-1’

Can anyone help me on Item 2 above? Or maybe you know an existing function or property of $object to achieve my objective?

Thanks a lot.