  The program SOFTSUSY can calculate tree-level neutrino masses in the R-parity
violating minimal supersymmetric standard model (MSSM) with real couplings. At
tree-level, only one neutrino acquires a mass, in contradiction with neutrino
oscillation data. Here, we describe an extension to the SOFTSUSY program which
includes one-loop R-parity violating effects' contributions to neutrino masses
and mixing. Including the one-loop effects refines the radiative electroweak
symmetry breaking calculation, and may result in up to three massive, mixed
neutrinos. This paper serves as a manual to the neutrino mass prediction mode
of the program, detailing the approximations and conventions used.
