how do i re-hydrate a core data URIRepresentation without knowing the PSC?

FROM : Ken Victor
DATE : Fri Jun 30 02:05:09 2006

given that i can "archive" an NSManagedOBject instance via:

[coder encodeObject: [[instance objectID] URIRepresentation] forKey:
@"objectIdKey"];

how do i go about getting back the NSManagedObject? more
specifically, managedObjectIDForURIRepresentation needs to be sent to
a PersistantStoreCoordinator instance and given that i'm in a
multi-doc environment, how do to find which PSC corresponds to a URI?
(same problem exists if i try to use objectWithID... ie, in a
multi-doc environment, how do i know which MOC to message?).

thanx,
ken