Hi gideonjc,
you are right..your netlist from DC do not contain these as these are physical cells...which do not account for the functionality of the design.
So you need to create these physical cells(VDD/GND,corner cells etc) during design planning stage and these pad cell locations are defined through a file called TDF...if you do not have TDF, ICC will place these physical cells for you automatically...
Once you nitialize your floorplan after creating Physical cells and specified their locations, filler cells will be placed between these physical cells for issues such as well continuity etc...which are DFM related
cheers