Did not know that I can't read minds, or if I can I chose to pretend I can't in this case.
I think there would be two components to it. The 2da edits adding the items properties to the correct haks and the scripting end.
Lets skip the 2da edits. One because I think they are more tedious, than hard and two, because I don't have more than a basic understand of how to go about them.The scripting end would be dependent on how the system should be implemented. Would we want characters to manually store PPs into the Storage Items, or do we just want them to add to the character's PP total? Would we want only equipped items to have the property, or would we want characters carrying around as many crystals as they want(the any number might only be balanced if you had to charge the crystals.) Would we want the properties only available to a Cognizance Crystals item, or any item?
I have a decent idea of how to add such a system(other than the 2da edits), but that is pointless if we don't know how it should be setup.