  We provide a description of the five-dimensional Higgs mechanism in
supersymmetric gauge theories compactified on the orbifold S^1/Z_2 by means of
the N=1 superfield formalism. Goldstone bosons absorbed by vector multiplets
can come either from hypermultiplets or from gauge multiplets of opposite
parity (Hosotani mechanism). Supersymmetry is broken by the Scherk-Schwarz
mechanism. In the presence of massive hypermultiplets and gauge multiplets,
with different supersymmetric masses, the radion can be stabilized with
positive (de Sitter) vacuum energy. The masses of vector and hypermultiplets
can be fine-tuned to have zero (Minkowski) vacuum energy.
