How to program another manufacturer's remote to operate a Panasonic device. - DVD Player/Recorder
To obtain the remote code you need to contact the manufacturer of the remote.
When a manuafacturer produces a universal remote they program another companies remote signals into the remote and then assign a code or a sequence of button presses to access those codes. These codes and processes to access do vary by manufacturer.
Here are some links to manufacturers that have Panasonic Codes in their products.