  The two-orbital model for manganites with both non-cooperative and
cooperative Jahn-Teller phonons is studied at hole density x=0.5 using Monte
Carlo techniques. The phase diagram is obtained varying the electron-phonon
coupling and the $\rm t_{2g}$-spins exchange. The insulating CE-type charge-
and orbital-ordered state with the $z$-axis charge $stacking$ observed in
narrow-bandwidth manganites is stabilized in the simulations. Its charge gap
$\Delta_{\rm CO}$ is much larger than the critical temperature $\rm k_B
T_{CO}$. Metallic-like A-type and ferromagnetic states are also obtained in the
same framework, and the phase boundaries among them have first-order
characteristics.
