Hi
you need to override the Address.php and set company required true as:
public static $definition = array(
'table' => 'address',
'primary' => 'id_address',
'fields' => array(
'id_customer' => array('type' => self::TYPE_INT, 'validate' => 'isNullOrUnsignedId', 'copy_post' => false),
'id_manufacturer' => array('type' => self::TYPE_INT, 'validate' => 'isNullOrUnsignedId', 'copy_post' => false),
'id_supplier' => array('type' => self::TYPE_INT, 'validate' => 'isNullOrUnsignedId', 'copy_post' => false),
'id_warehouse' => array('type' => self::TYPE_INT, 'validate' => 'isNullOrUnsignedId', 'copy_post' => false),
'id_country' => array('type' => self::TYPE_INT, 'validate' => 'isUnsignedId', 'required' => true),
'id_state' => array('type' => self::TYPE_INT, 'validate' => 'isNullOrUnsignedId'),
'alias' => array('type' => self::TYPE_STRING, 'validate' => 'isGenericName', 'required' => true, 'size' => 32),
'company' => array('type' => self::TYPE_STRING, 'validate' => 'isGenericName', 'required' => true, 'size' => 64),
'lastname' => array('type' => self::TYPE_STRING, 'validate' => 'isName', 'required' => true, 'size' => 32),
'firstname' => array('type' => self::TYPE_STRING, 'validate' => 'isName', 'required' => true, 'size' => 32),
'vat_number' => array('type' => self::TYPE_STRING, 'validate' => 'isGenericName'),
'address1' => array('type' => self::TYPE_STRING, 'validate' => 'isAddress', 'required' => true, 'size' => 128),
'address2' => array('type' => self::TYPE_STRING, 'validate' => 'isAddress', 'size' => 128),
'postcode' => array('type' => self::TYPE_STRING, 'validate' => 'isPostCode', 'size' => 12),
'city' => array('type' => self::TYPE_STRING, 'validate' => 'isCityName', 'required' => true, 'size' => 64),
'other' => array('type' => self::TYPE_STRING, 'validate' => 'isMessage', 'size' => 300),
'phone' => array('type' => self::TYPE_STRING, 'validate' => 'isPhoneNumber', 'size' => 32),
'phone_mobile' => array('type' => self::TYPE_STRING, 'validate' => 'isPhoneNumber', 'size' => 32),
'dni' => array('type' => self::TYPE_STRING, 'validate' => 'isDniLite', 'size' => 16),
'deleted' => array('type' => self::TYPE_BOOL, 'validate' => 'isBool', 'copy_post' => false),
'date_add' => array('type' => self::TYPE_DATE, 'validate' => 'isDate', 'copy_post' => false),
'date_upd' => array('type' => self::TYPE_DATE, 'validate' => 'isDate', 'copy_post' => false),
),
);