  Production of strange hadrons in elementary and heavy-ion reactions is
studied with the hadronic transport approach SMASH (Simulating Many Accelerated
Strongly-interacting Hadrons). The poorly known branching ratios of the
relevant hadronic resonances are constrained from the known elementary hadronic
cross sections and from invariant mass spectra of dileptons. The constrained
model is employed as a baseline to compare to heavy-ion-collision experiments
at low energies ($E_\text{kin} = 1-2A\,\text{GeV}$) and to predict some of the
upcoming pion-beam results by HADES, which are expected to be sensitive to the
resonance properties. The employed vacuum-resonance approach proves to be
viable for small systems at these energies, but for large systems additional
in-medium effects might be required.
