Yamaha receiver volume control with BenQ projector remote

[jmgallo23]

Recently getting setup a home theater and can't seem to get the projector remote to control the receiver volume. BenQ TK850i and Yamaha RX-V685. I've got ARC working properly and everything sound good, but right now I'm forced to use the receiver remote, and can't figure out how to give the project remote access to control it. I've already turned on Electronic Control which allows me to turn on and shut off both devices together, but no volume control. Any ideas?