Hi Antonio
WM movements are not same as IM movements. Serial numbers are linked to IM movements so you will have tracking but for WM movements that do not communicate back to IM you can not have tracking..
One possible solution if your serial number is equal to your batch number. Means you have batch management as well. You classify your batch with serial number, then may able to do tracking on batches in WM and linking them to serials.
This seems to be only solution, no other solution possible it look like to me. But all the best.