Shouldn't using the clutch to down shift disengage cruise control?

Hi: I have been driving stick shift all my life and have been quite successful in the use of
down shifting in many conditions to save wear and tear on brakes.  For the past 6 years
I have been driving a Mini Cooper Hard Top with cruise control and stick shift.  When
down shifting, the cruise control disengaged and the car slowed down.  I just traded in
that great Mini for a new Mini with stick shift and cruise control only to find that in the
new car, using the clutch does not disengage cruise control.  First time I tried the cruise
control on the new car, when I down shifted as I usually do while approaching a
changing traffic light, the car shot forward instead of slowing down bringing me
uncomfortably close to a car in front.  This was a nasty revelation to me.  It seems to
that in order to disengage the cruise control I have to either hit the brake or hit the
cancel button.  Of course I have been back to Mini service and they are "looking into it".  
Even though they understand how manual shift works and that it should disengage the
cruise control, they are confused by the whole thing.  So am I!  What's your take on
this?