Hi Fuji,
The basic premis of an atc service outside controlled airspace under IFR is that unless the pilot informs the atco he does not require an approach control service, (even if you are transitting the area and not inbound to the airfield where the atc service is being provided from), the atco is obliged to use standard separation to seperate you from other IFR aircraft. Hence you may be routing over a beacon outside the atz, but still be asked to climb, descend to or maintain a specified level.
Many atc units with radar will give you such procedural "clearances" until they can provide a radar service.
Good airmanship dictates that you participate in this sort of service where no radar is available,(especially if you are IFR and IMC), but in the FIR it is not obligatory, just common sense really.