If it's a sinlge LNB how is there two feeds coming from it???? are you sure it's not a dual or quad LNB??
If you have two feeds (cables) coming into the room where your duo2 is then connect one to tuner A and the other to Tuner B.... simple setup in tuner configuration will suffice for both feeds....
What version of CCcam are you using?? try using 2.3.0 to be able to watch one channel and record the other with the latest images....
