Hi Rose,
You can also do this using OSC raw strings.
Syntax is the same as QLX.
To see what's happening I also usually designate a user id in the string so from the diagnostics window in EOS you can see if string is being received.
From memory string would be something like:
$ </5> Cue # * \r
Replace # with cue list number
Replace * with cue number
In the OSC setup you will need to put the IP address of the MAIN console and put the port number you have setup on the EOS/GIO/ION as the serial RX port.
Unfortunately i can't get access to a computer for the moment to test and confirm this bit it's quite simple.
ETC Serial command list
http://www.etcconnect.com/Support/Articles/Eos-Family-Serial-Command-Syntax.aspx
Hope this helps.
Adam