If you are trying to feed both tuners of a 322 with a single coax (and separator) from the dish, you probably don't have a DPP twin. Recommend getting one. Alternatively, you could bring both outputs of your DP twin down to the two tuners of your 322.
DishPro Plus will allow you to run one line from the LNB, to a DPP separator to "split" the signal into the satellite 1 and 2 tuners on the 322. The Separator will not work with DishPro (non-Plus) equipment. So you will need the Plus LNB, or an external switch with what you currently have