  The $B \to \pi$ and $B \to K$ transitions involved in hadronic B decays are
investigated in a phenomenological way through the framework of QCD
factorization. By comparing our results with experimental branching ratios from
the BELLE, BABAR and CLEO Collaborations for all the B decays including either
a pion or a kaon, we propose boundaries for the transition form factors $B \to
\pi$ and $B \to K$ depending on the CKM matrix element parameters $\rho$ and
$\eta$. From this analysis, the form factors required to reproduce the
experimental data for branching ratios are $F^{B \to \pi}= 0.31 \pm 0.12$ and
$F^{B \to K}= 0.37\pm 0.13$. We calculate the direct CP violating asymmetry
parameter, $a_{CP}$, for $B \to \pi^{+} \pi^{-} \pi$ and $B \to \pi^{+} \pi^{-}
K$ decays, in the case where $\rho-\omega$ mixing effects are taken into
account. Based on these results, we find that the direct CP asymmetry for
$B^{-} \to \pi^{+} \pi^{-} \pi^{-}$, $\bar{B}^{0} \to \pi^{+} \pi^{-} \pi^{0}$,
$B^{-} \to \pi^{+} \pi^{-} K^{-}$, and $\bar{B}^{0} \to \pi^{+} \pi^{-}
\bar{K}^{0}$, reaches its maximum when the invariant mass $\pi^{+} \pi^{-}$ is
in the vicinity of the $\omega$ meson mass. The inclusion of $\rho-\omega$
mixing provides an opportunity to erase, without ambiguity, the phase
uncertainty mod$(\pi)$ in the determination of the CKM angles $\alpha$ in case
of $b\to u$ and $\gamma$ in case of $b \to s$.
