As mentioned before, in tuner configuration, you are telling the receiver what you have connected to each tuner and how you have connected it.
You are jumping the gun, because the hardware is not connected correctly. You should be asking how to connect up the LNBS and Diseqc switches. I don't mean to cause offence, but if I were the one requiring help, I would put all my cards on the table, instead of having to be asked.
A diseqc switch switches between LNBs. So if you connect two wires from the same LNB, it will be switch from 28.2 to 28.2 again. That is not the way to do it.
I am guessing you have two tuners. If that is the case, you need two diseqc switches. 28.2 LNB will have wire going to both switces, 13e LNB will also have wires to both switches.
As in this picture
Please feel free to post a picture/diagram of how you have connected things up.