One receiver must be a Master, the other the slave. Most often the master does the dish moving and LNBF settings. The Slave receiver sort of "goes along for the ride" and shares the signal being gathered.
So in this instance the 922 does the dish moving, and H/V polarity setting. The signals are shared by the splitters. The switch allows the DVB receiver to go between C and Ku bands.
The dish used here is most likely a big dish, with acutator type mover. The 922 type receivers don't know anything about H-H motors or DISEQC signaling.
The other way to do it, is have the DVB receiver be the Master, with the 922 or analog box connected to the "loop out" or secondary IF out on the DVB box.
Now the DVB (via
Vbox) moves the dish and controls the LNB. The 922 is now the slave, and will only see the satellite and polarity the LNB is set to from the DVB receiver.