MTS Import in iMovie11 (Canon Legria HF R106)

I have stored a lot files from this camera on an external HDD before i started using a Mac with iMovie11. Importing new clips directly from the camera works

(see also KB Article http://support.apple.com/kb/TS3634?viewlocale=en_US ), if i go via the camera import, but how can i access the old files with iMovie11?

I tried conversion with handbrake, but quality is not as good as the direct import of new files with the camera itself (a lot of fragments in fast moving scenes).

Any suggestion with acceptable quality and speed?

To the Apple Support Team: It would be great to have a direct import of these files in iMovie12! :-)

BR and thx