I got it. After reading some of the documentation on
DataService.getItem I learned that the "ItemReference" object that
is given back extends "AsyncToken". This means you should either
bind to the "result" property of the ItemReference or add a
responder to it (i.e. itemRef.addResponder).
Then once the data is retrieved your "result" or "fault"
methods (from the mx.rpc.IResponder interface) will be