Audio level control on remote Frontend

[pinnerite]

I am running MTV 29.1
I can control the volume from the frontend situated on the backend server from a tiny wireless keyboard.

However, from a remote frontend I cannot control the volume from its standard wired keyboard.

The sound setting from Pulseaudio is:
Analogue Surround 2.1 Output + Analogue Stereo Input

Have I made a setting mistake?

[bill6502]

mythfrontend settings for audio: "Use internal volume controls" would be my first (probably only) place to check.