Solved... (Almost!) 
Someone pointed out that Canon has a software (they said there was no driver for Mac OS X so I had stopped looking...) But if it may help others, there is a ''CameraWindow'' for Mac OS X 10.6, 10.7 and 10.8 available.
As soon as I installed it, I could capture both from Adobe Premiere CS6 and iMovie.
One problem remaining though : the noise (feedback-like) that gets out from... the system's sound card ! (when capture is ongoing). I have to shut down the volume completely. Never had this issue under Windows, need to figure out why this happens now.
Jeff thanks again for your assistance, even though the solution was somewhere else.
If anyone has a clue for the noise issue ... please let me know
Rob