Yes, C & D works as well but the OP says he hoped A & B would work. I was just confirming that.
To the OP, if you have a cable in as well as satellite in, the cable in connection usually goes to the Winegard (or similar) power supply wall plate and is used to switch between OTA TV (power light on) and cable (power light off). This can be modified in many cases to allow it's use with satellite as well by adding an A/B switch to the wall plate. You can give it a try by simply removing the wall plate, and disconnecting the coax on the back that is connected to the port labeled Cable. Connect that to the satellite receiver (may need to add an extension) and if you get satellite TV then it will work with the A/B switch in the mix. If that works you just run that coax you disconnected to 1 port of an A/B switch and then run a jumper from the A connection back to the wall plate and a jumper from the B connection to the satellite. If it does not work then there could be other splitters in the coach that would prevent the use of satellite as Roy mentions above.