Okay... after a quickscout around...
It is not possible (apparently).
That said... you do have alternatives;
If keepig it as Checkbox/Radial is important, then you may need to re-order the form code so that clickig the vlaue label will act the same as clicking the item (being the heckbox/radial).
Following the above, you can apply a visual marker to indicate the active area's, (so for the value label, apply a class and either add a subtle border or apply a background-colour).
An alternative approach isto replace the Checkbox/radial with a dropdown list. For Checkboxes you can apply multi-select, for the Radial a single option only is equal.
Though visually different, these will have exactly the same results.