Form submit problem

Hello.

I am developing a custom module and want to add an additional field on Expense report creation.

  1. I have created my module
  2. I have created the hook
  3. I have set an SQL file, so a column named fk_soc is added in llx_expensereport (fk_soc int(11))
  4. The required field (DropDown to select Third party) is shown on the Expense report create page
  5. On form submit, field ‘fk_soc’ is not populated

My code:

On “expensereport/card.php” I have

$reshook = $hookmanager->executeHooks('formObjectOptions', $parameters, $object, $action);

so in my class, I have this function:

    public function formObjectOptions($parameters, &$object, &$action, $hookmanager)
    {
        global $conf, $user, $langs;
        $error = 0; // Error counter

        if ($action === 'create') {
            print '<tr><td  class="tdtop">' . $langs->trans('Customer') . '</td>';
            print '<td>';

            $form = new Form($this->db);
            $societe = new Societe($this->db);

            print img_picto('', 'company') . $form->select_company($societe->id, 'fk_soc', 's.fournisseur=1', 'SelectThirdParty', 0, 0, null, 0, 'minwidth300 widthcentpercentminusxx');
            print '</td>';
            print '</tr>';
        }

        if (!$error) {
            return 0;
        } else {
            dol_print_error($this->db);
            return -1;
        }
    }

I am attaching the form create screen.