I have the same problem as well and still searching for a solution. What I have experienced so far with ControlCommand() is following:
ControlCommand("Title","text", "IsChecked","") --> this always return 0 no matter the botton is check or not
ControlCommand("Title","text", "UnCheck","") --> this is also not working for my case
But...
ControlCommand("Title","text", "Check","") --> this look like is working, I can get unchecked box to get a check thus not sure if you have try this for your case.