  The first observation of $\bar{B}^0_d\to D^0\bar{K}^0$ and $\bar{B}^0_d\to
D^0\bar{K}^{*0}$ transitions by the Belle Collaboration allows us to do a
complete isospin analysis of $B\to DK^{(*)}$ decay modes. We find that their
respective isospin phase shifts are very likely to lie in the ranges $37^\circ
\leq (\phi_1 -\phi_0)_{DK} \leq 63^\circ$ (or around $50^\circ$) and $25^\circ
\leq (\phi_1 -\phi_0)_{DK^*} \leq 50^\circ$ (or around $35^\circ$), although
the possibility $(\phi_1 -\phi_0)_{DK} = (\phi_1 -\phi_0)_{DK^*} = 0^\circ$
cannot be ruled out at present. Thus significant final-state rescattering
effects are possible to exist in such exclusive $|\Delta B| = |\Delta C| =
|\Delta S| =1$ processes. We determine the spectator and color-suppressed
spectator quark-diagram amplitudes of $B\to DK$ and $B\to DK^*$ decays, and
compare them with the corresponding quark-diagram amplitudes of $B\to D\pi$ and
$B\to D\rho$ decays. The effects of SU(3) flavor symmetry breaking are in most
cases understandable in the factorization approximation, which works for the
individual isospin amplitudes. Very instructive predictions are also obtained
for the branching fractions of rare $\bar{B}^0_d \to \bar{D}^0 \bar{K}^{(*)0}$,
$B^-_u \to \bar{D}^0 K^{(*)-}$ and $B^-_u \to D^- \bar{K}^{(*)0}$ transitions.
