I had asked the same question many months ago and never got an answer or resolution.
Ironically I ended up still using my remote I had left over from Shaw just for the turning on/off of both the TV and audio receiver together as the Telus remote wouldn't do it,,, for some reason that nobody could answer.
I went through all the pairing codes available for the receiver, and like you, it could only manager volume control.
I gave up considering I don't anticipate staying with this Telus system long enough to bother.