For the published equipment to create shared objects that instantiate the ISPFTEFSharedEquipment interface, one of the realized interfaces on the published equipment must be related to the SPFTEFSharedMappedInterface relationship definition.
ISPFTEFSharedEquipment is already related to IEquipment, which is often used on published equipment class definitions so there would be no need to create an additional relationship. To see what is related to these shared object interfaces, find them in the Desktop Client and then use the Export Data command to browse the structure.