Administering custom items by doctors

[Spartakus_PSP]

I was wondering how the healer mech serum can be both used by a pawn and be administered (by a medical bill like doing surgery), though it doesn't appear to be a drug.
I found nothing in the XML files that should make administration of the healer serum by doctors possible (I've compared it's XML code to the ressurector serum's XML code)

Anyone has an idea how this can be achieved?