UNKIKE AKnowles, I generally wait to have the vehicle parked before setting the parking brake, where he says he uses it while parking, must be a hand brake turn or something to that effect. I know when I was younger and drove semis for a living you were instructed to use the trailer brake when on a hill to prevent rollback. It is just common sense to release the brakes whether it be a hand brake or a trailer brake while your feet are on the clutch and throttle. This is the way I have always done it and do not have a problem doing it in my Boxster, if and when I have premature clutch failure I'll be the first to let the forum know.
