Smartphone remote control?

I’m seeking a wifi smartphone solution to control the volume on my home stereo. For that a strong contender is Logitech Harmony, which uses “IR Blasters”. I do not want to place an IR-Blaster in front of my stereo cabinet (there is no space and they are ugly anyway), but instead want to use a provided 3.5mm jack in the rear of the preamp for “IR-Direct Input”. Is there a product that will detect the IR-output of the Logitech Harmony and control the volume on my preamp? Better yet, is there a solution where I can skip the IR transmission altogether and wire the Logitech hub directly to the preamp?

Thanks!

My preamp is: Hegel P30
http://www.hegel.com/support/support-for-p30/210-p30-manual-english (see page 7)

FWIW, here is my listening room:
http://ascent-design.com/audio/index.html