When a mac with built in iSight chooses the iSight as primary source, you can't get it changed to DV-link...
this script makes you choose to enable or disable your iSight,
thus ... Problem solved
thus you can restart premiere pro, and have a normal isight-less capture ...
It could be that you cannot get the preview on screen but just reffer to your camera screen in that case.
recording the image does work !