Smooth "pan and zoom" effect?

Is it possibile to achive smooth movements with "pan and zoom" in kdenlive?
Something like this http://vimeo.com/17408261 as explained here http://michalfapso.blogspot.com/2010/12/how-to-create-photo-slideshow.html
I tried "pan and zoom" effect but it's very hard to smoothly reduce speed the panning, the only way I found is to add several keyframes with a progressively smaller movement, but it's very handmade and frustrating :-(

Thanks

I think this is called "spline-based interpolation" and unfortunately, it's not available in Kdenlive - yet.

http://kdenlive.org/forum/keyframes-spline-based-interpolation

Thanks for information, I hope it will embedded soon.