I added in Builder a vertical slider to control the volume of my Denon Receiver (AVR 2300W). I am using the "Denon RS232/TCP All Models Main Zone Slider" device and the volume feedback from "Denon Receiver Main Zone - RS232 and TCP/IP". Well, after syncing to my iPad, I can control the volume of the receiver using the slider, but it does not display the actual volume level on Denon. Is it supposed to? If it is, what could I be missing?