on most DVB systems polarity is controled by voltage through the coax
if your c-band lnbf can accept votage controlled polarity switching then the DVB receiver can do it....... on older c band lnb's ( using a corotor , polorotor ) then polarity switching is controled with the analog receiver using voltage( supplied by three wires) to control a servo on those type of feedhorns
there are only a few DVB receivers that can control the voltage on a corotor / polorotor type feedhorn.