I don't do IWP, so this may not work, but it's worth a try:
Place your radio button formatted field on your layout.
In layout mode, select the field and choose Format | Button Setup... to set it up as a button. Select the script you want to perform.
Now connect to your IWP DB via browser and see if the script is performed when you click the radio button.
I've also done what Phil suggests but with a little twist, possibly overthinking things, possibly not.
Put your YES/NO radio buttons down.
Put a transparent box over the "YES" and setup it's button action to setfield=Yes then perform the script.
Put a 2nd transparent box over the "NO" and setup it's button action to setfield=No then perform the script.
Pretty much the function that Phil was getting at, but it lets you differentiate between the yes and no entries on the button set. I honestly didn't try it direct on the button set...the transparents may not be needed in the first place...I hadn't considered it.