  A localized configuration is found in the 5D bulk-boundary theory on an
$S_1/Z_2$ orbifold model of Mirabelli-Peskin. A bulk scalar and the extra
(fifth) component of the bulk vector constitute the configuration. $\Ncal=1$
SUSY is preserved. The effective potential of the SUSY theory is obtained using
the background field method. The vacuum is treated in a general way by allowing
its dependence on the extra coordinate. Taking into account the {\it
supersymmetric boundary condition}, the 1-loop full potential is obtained. The
scalar-loop contribution to the Casimir energy is also obtained. Especially we
find a {\it new} type which depends on the brane configuration parameters
besides the $S_1$ periodicity parameter.
