  The present paper deals with a next-to-leading order analysis of the
radiative $B \to K^* \gamma$ decay. Working in the PQCD approach developed by
Szczepaniak {\it et al.}, we compute the correction, coming from a single gluon
exchange with the spectator, to the essential form factor. Since the branching
ratio gets much above the experimental data, although in agreement with other
theoretical models predictions, we take into consideration the effects of
complex flavour couplings in the squark sector. Finally, we discuss these SUSY
implications on the branching ratio and direct CP asymmetry values and impose
bounds on the squark mixing parameter $(\delta_{23}^d)_{LR}$.
