Is there a multiswitch on the back of the Phase II dish?
Why are you upgrading to a 5x8 switch? With two DVRs you only need four lines with the attached switch on the PH II dish.
If for more than four outputs, you have two ways to do it. 1) disconnect the attached switch and connect the lines from the LNBs to the same inputs on the 5x8. or 2) attach the four lines from the attached switch to the four sat inputs on the 5x8. Power is supplied using another coax connected to the power supply.