Schleicher directional air vents

Hi, All,

my ASW-19 has three different air vents in the cockpit -- one in the
nose that's controlled
by a handle above the instrument panel, plus two holes in the
sidewalls. The nose vent
can get more or less closed, but there isn't any way to control the
side vents. It occurs to
me that there should be an adjustable directional vent in those side
holes -- it's been a long
time since I've flown a K-21, but it had those nice things that could
direct air up along your
canopy.

Is that what should be in my plane? If so, I have no idea what
happened to my original vents.
Is there something else that people use?

Thanks,
-- Matt