Enabling Unitiqute remote control volume controls ?

How do I enable the volume + / - controls and mute on the Unitiqute remote control handset?

I've looked through the set up manual and the reference manual but can't see where to enable them. I've tried de-energising the player and remote, waiting and re-energising them a factory settings reset, everything in the configuration menus. 

In the factory settings menu there is a facility to see recent commands. I can see the commands going from the RC handset to the player from the volume keys but they just aren't doing anything. Everything else on the RC works  (though I still don't have the physical network set up) so I assume it's something in the config.

I'm using it as a standalone player just now, not through an amp (it sounds fantastic on its own and it has more than enough welly for my listening room so no need for one).