Hey Mate, out of curiosity did you make any progress with this? I am trying to control a Gefen AV over IP system (Using the EXT-HD2IRS-LAN boxes for HDMI Tx and Rx) from Q-Sys and am not having any luck. It seems we may be in a similar boat, I can control the devices from telnet or the webGUI no worries, but I'm not having any luck sending commands from Q-Sys. I suspect I'm going about it the wrong way, trying to use command buttons to send a string via TCP to the IP Address of the receiver on Port 23.
Any advice would be much appreciated