[PDF-Forms] Referencing choice fields within FDF

[Mark Patterson (s)]

I have a radio button with (say) three sub elements. I am trying to allow a user who clicks on a "on" radio button to turn it off. I am aware of the setFlag (for bitpos 15) that will supposedly enable this. I am unable to get this to work, however. I tried to then insert some _javascript_ into a field using the FDF, but it appears that I am unable to reference the sub-field. I have tried using the field name (ex: C0130) and the element name (C0130.1). What am I missing?