Heh.. I never do a one leg over the back dismount on my carbon bike or on any bike anymore. I've gotten into the habit of unclipping one foot as I slow down, getting off the saddle to put one foot down as I slow to a stop and then unclipping my other foot once I've come to a full stop. It seemed to be the only reasonable way to ride with clipless pedals.

Sheldon Brown describes it this way: http://sheldonbrown.com/starting.html
What I wasn't aware of before I read his article was this:

"
Some Wrong Ways:


The Cowboy Mount is popular among cyclists who learned to ride on a bicycle that was too large for them. Indeed, this is the only way to get started on a bike that is seriously too tall for the rider. This dubious technique involves standing next to the bike, putting one foot on a pedal, then swinging the other leg over the saddle while the bicycle is in motion.

• The cowboy mount places the rider's weight on the bicycle while it is leaning over at a sharp angle. This puts considerable lateral stress on the frame and the wheels. Bicycle wheels, in particular, are not designed to withstand serious sideways stresses, and this poor mounting technique is very hard on your wheels."