You would need a remote that you can reprogram the keys (so that you can assign a different key for that function) or another remote with the same keys.
On a side note, I personally wouldn't even bother with it. That type of Dolby is a fake surround which simply converts a stereo input into surround audio. It's not the same as a true surround audio track.
On a side note, I personally wouldn't even bother with it. That type of Dolby is a fake surround which simply converts a stereo input into surround audio. It's not the same as a true surround audio track.