As with most companies I have been with, if there is no overlay approach associated with the "pure" NDB approach which may not not be contained within the FMC's data base, then the approach must be flown in raw data. An approach may be built for reference purposes only.
Beware... of the man from the FAA, CAA or any other agency who may be riding the jump seat, and if a non data base approach is created and flown using LNAV and VNAV.