  In this paper we are concerned with numerical methods for the one-sided event
location in discontinuous differential problems, whose event function is
nonlinear (in particular, of polynomial type). The original problem is
transformed into an equivalent Poisson problem, which is effectively solved by
suitably adapting a recently devised class of energy-conserving methods for
Poisson systems. The actual implementation of the methods is fully discussed,
with a particular emphasis to the problem at hand. Some numerical tests are
reported, to assess the theoretical findings.
