  Majorana bound states can emerge as zero-energy modes at the edge of a
two-dimensional topological insulator in proximity to an ordinary s-wave
superconductor. The presence of an additional ferromagnetic domain close to the
superconductor can lead to their localization. We consider both N-S and S-N-S
junctions based on helical liquids and study their spectral properties for
arbitrary ferromagnetic scatterers in the normal region. Thereby, we explicitly
compute Andreev wave-functions at zero energy. We show under which conditions
these states form localized Majorana bound states in N-S and S-N-S junctions.
Interestingly, we can identify Majorana-specific signatures in the transport
properties of N-S junctions and the Andreev bound levels of S-N-S junctions
that are robust against external perturbations. We illustrate these findings
with the example of a ferromagnetic double barrier (i.e. a quantum dot) close
to the N-S boundaries.
