Using a QCD relativistic potential model, previously applied to the calcula
tion of the heavy meson leptonic constants, we evaluate the form factors go
verning the exclusive decays B --> rho lv: B --> K*gamma and B --> K*l(+)l(
-). In our approach the heavy meson is described as a Q (q) over bar bound
state, whose wave function is solution of the relativistic Salpeter equatio
n, with an instantaneous potential displaying Coulombic behaviour at small
distances and linear behaviour at large distances. The light vector meson i
s described by using a vector current interpolating field, according to the
Vector Meson Dominance assumption. A Pauli-Villars regularized propagator
is assumed for the quarks not constituting the heavy meson. Our procedure a
llows to avoid the description of the light meson in terms of wave function
and constituent quarks, and consequently the problem of boosting the light
meson wave function. Assuming as an input the experimental results on B --
> K*gamma, we evaluate all the form factors describing the B --> rho, K* se
mileptonic and rare transitions. The overall comparison with the data, when
ever available, is satisfactory.