The motion of the planets are what defines the term rather than the nature of the celestial object itself,of course their observed motion is conditioned by the observed motion of the Earth itself and particularly now that it is possible to partition inner and outer retrogrades in terms of a faster moving Earth or a faster moving Venus and Mercury.
It is easy to ascertain that Venus moves in the opposite direction to the background stars when moving from behind the Sun to its widest point from our vantage point on a moving Earth and moves in the ecliptic direction of the background stars while moving in front of the Sun -
http://www.youtube.com/watch?v=MdFrE7hWj0A
In visual terms it looks like this -
http://www.masil-astro-imaging.com/S...age%20flat.jpg
The relevance of the retrograde direction change depending on whether Venus is moving in front of the Sun from our point of view or behind the Sun should be taught to students without waiting for any educational authority to come around to this new point of view and dismissing the false older perspectives which do not take modern graphics and imaging into account.