  We present a method for populating dark matter simulations with haloes of
mass below the resolution limit. It is based on stochastically sampling a field
derived from the density field of the halo catalogue, using constraints from
the conditional halo mass function n(m|{\delta}). We test the accuracy of the
method and show its application in the context of building mock galaxy samples.
We find that this technique allows precise reproduction of the two-point
statistics of galaxies in mock samples constructed with this method. Our
results demonstrate that the full information content of a simulation can be
communicated efficiently using only a catalogue of the more massive haloes.
