xfmLocateOp in fence mode , does I need to scan all models ?

I'm doing a dgn scan in fence mode ; there are some features, in a reference, that are not found ( shapes ) ; I have tries to scan all model , doing a xfmLocateOp_setModelRef() , but the model parameter seems ignored ( the returned elements are always the same , in active model )

how can i retrieve features in reference models ?

sometimes these features are shape that contain entirely my fence , are these larger shapes returned as well ? i would need these too ( to determine the zone where i dis the scan )