Chaps,
All this talk of HV curves, surely nothing to prohibit entry to the HV curve unless local operating regulations prevent you from being in it.
The conditions the HV diagrams are built for are not those usually met on the approach, steep approaches provided an appropriate technique is used for the aircraft type may well be absolutely fine. Avoid going into the curve for departure but not necessarily on the approach (for commercial operations where I am from any way).
Some of the larger types have the HV curve in the limitations section at which point they must be respected.
Gary