Check through the menus on your TV and see it you have the option of "Fixed' or 'Variable' output from the Audio Outs.
Not many TV's have it, but some do. If you have this feature, set it to 'Variable' and you TV remote will change the volume on the speakers.
If not, then I'm not sure what you can do except get a new amp and speakers.
One other question, does the Aergo M have remote capability, and you simply don't have the remote, or is remote capability not an option?
Steve/bluewizard