  We extend the results of Mirabelli and Peskin to supergravity. We study the
compactification on S_1/Z_2 of Zucker's off-shell formulation of 5D
supergravity and its coupling to matter at the fixed points. We clarify some
issues related to the off-shell description of supersymmetry breaking a la
Scherk-Schwarz (here employed only as a technical tool) discussing how to deal
with singular gravitino wave functions.
  We then consider `visible' and `hidden' chiral superfields localized at the
two different fixed points and communicating only through 5D supergravity. We
compute the one-loop corrections that mix the two sectors and the radion
superfield. Locality in 5D ensures the calculability of these effects, which
transmit supersymmetry breaking from the hidden to the visible sector. In the
minimal set-up visible-sector scalars get a universal squared mass m_0^2 < 0.
In general (e.g. in presence of a sizable gravitational kinetic term localized
on the hidden brane) the radion-mediated contribution to m_0^2 can be positive
and dominant. Although we did not build a complete satisfactory model,
brane-to-brane effects can cure the tachyonic sleptons predicted by anomaly
mediation by adding a positive m_0^2 which is universal up to subleading
flavour-breaking corrections.
