You must request shell execution rights from iRex. It will be another download from the IDS. Once you have that installed your GTG, just follow yokos's excellent directions.
See
Here
FYI, It would probably be best to check the MAC number on the setup page with your iLiad on. The one on the back of my unit is different than the one noted on the top of the setup page (upper right hand corner if I remember correctly).
This will eliminate the need to email iRex to get the situation rectified.