PM BAPIs for Equipment and Functional Locations

I'm trying to locate BAPIs that can return data containing the structure of equipment to present in a "tree view" that would resemble something like:

Functional Location 1

--- Functional Location 1.1

--- Installed Equipment 1.1A

--- Sub-Equipment 1.1A-1

--- Installed Equipment 1.1B

Currently I can generate the hierarchy of Functional Locations with no problem. Also, I have no problem getting a list of all equipment. What I can't seem to find is a BAPI that will return the equipment installed at a given functional location nor can I find a BAPI that will retrieve parent (superior) equipment for a given equipment. Any suggestions are very much appreciated.