It would work, but then you would have only full positive pitch or full negative, which would be pretty hard to continally be flipping a switch to keep it in the air. IMO the best way of doing it is, like stated in the above post, to set it up so that it acts like the pitch on a heli head. Mid stick would be at half power or less, and neutral pitch. Full stick would be full power and full positive pitch. Idle stick would be full power and full negative pitch. There would be throttle and pitch curves, most likely in the heli mode in your radio, that would make each stick position proportional to the amount of throttle and pitch fed into your system.

A good Idea would be to use the Idle Up switch to toggle in between VPP mode and "normal" mode so that you can turn off the Variable pitch function.

Hope this helps,
Brandon