Indeterminate state for toggle buttons?

I'm working on a tablet based application where an agent would be going through and answering a series of yes/no questions. This is running on Windows 7 and naturally the standard windows controls aren't as touch friendly as they could be.

Currently the Yes/No questions are presented as a pair of radio buttons, but we're considering making these more modern / touch friendly, and we're looking at replacing them with a windows phone style toggle button.

The gotcha is that our design requirement does not permit us to have any of these yes/no answers defaulted to either option, that is the control must be in an indeterminate state on initial display (the user can't put the control in an indeterminate state themselves).

So the only design I can think of would be a toggle switch where the thumb of the switch sits right in the middle, then the user goes down the form either touching the left or right side of the control, or alternatively, flicking the thumb left or right to answer the questions. Does this seem like an intuitive way to present the control?