Sorry to drag this back up, but I'm having a similar issue now using Creo 3.0.
I essentially want to add a new cooridnate systems to a 6.3mm Faston part (taken from here).
One ref on the flat plate (mating connector), a second centered on the disc surface on the cable side.
Maybe the part I've imported prevents me from doing this? But no matter what I try, I cannot get it working. It looks like the menus are slightly different too, maybe I'm not using the correct "Reference" menu?