  A large class of D-branes in Calabi-Yau spaces can be constructed at the
Gepner points using the techniques of boundary conformal field theory. In this
note we develop methods that allow to compute open string amplitudes for such
D-branes. In particular, we present explicit formulas for the products of open
string vertex operators of untwisted A-type branes. As an application we show
that the boundary theories of the quintic associated with the special
Lagrangian submanifolds Im \omega_i z_i = 0 where \omega_i^5=1 possess no
continuous moduli.
