Unable to get storage using [list_share]

[Luccio96]

I tried to retrive volume status using this command, but I got empty output:

syno.dsm.listShares({
     additional : "volume_status"
   }, function(error, data) {
    console.log(data)  ;
  });

{ shares: [], total: 0 }

Using the listShares without parameter I got this output:
{ shares: [ { desc: '', is_usb_share: false, name: 'Backup', uuid: 'bd2be816-11f7-4c70-a78f-239bd8971239', vol_path: '/volume1' }, { desc: 'user home', is_usb_share: false, name: 'homes', uuid: '62e4370c-cf28-4320-8076-1430a8d5d97e', vol_path: '/volume1' }, { desc: '', is_usb_share: false, name: 'Moreno', uuid: '7b10e336-1f52-4256-bc6b-2f54650da33f', vol_path: '/volume1' }, { desc: 'NAKIVO Repository', is_usb_share: false, name: 'NAKIVO_Repository', uuid: 'a4f76933-0aec-4221-82c1-78cf0f609af5', vol_path: '/volume1' }, { desc: 'System default shared folder', is_usb_share: false, name: 'web', uuid: '16fe6bd7-1610-477b-b4de-8bbf607228d8', vol_path: '/volume1' } ], total: 5 }

From the API documentation:

additional parameter is optional and when additional option is requested, responded objects will be provided in the specified addiontal option.

So what is the problem?