choosing player position

[pinball]

I'm trying to create a new defensive formation using the PDS. When I create a new formation, it always gives me the same set of players to work with (SF1, SF2, SF3, CB1, CB2, etc.). How do I change position for the player icon. For example, I want to use DB1 and DB2 instead of SF2 and SF3.

I can't figure out how to do this in the PDS. The only way I've figured out how to achieve this is by changing it later on when I edit the depth charts. Can it be edited within the PDS?