How do I use my lg tv remote to turn my amp up it connected by digital lead

[Waynesct1]

I've just connected my tv to my amp threw a digital lead but I can only turn it up by my amp how can I get the tv remote to do it

 

[popatim]

Disconnect the amp and use the tv speakers.
Theres no volume info in the digital audio stream so it's just like using a line level output.