  Within the light-front framework, form factors for $P\to P$ and $P\to V$
transitions ($P$: pseudoscalar meson, $V$: vector meson) due to the
valence-quark configuration are calculated directly in the entire physical
range of momentum transfer. The behavior of form factors in the infinite quark
mass limit are examined to see if the requirements of heavy-quark symmetry are
fulfilled. We find that the Bauer-Stech-Wirbel type of light-front wave
function fails to give a correct normalization for the Isgur-Wise function at
zero recoil in $P\to V$ transition. Some of the $P\to V$ form factors are found
to depend on the recoiling direction of the daughter mesons relative to their
parents. Thus, the inclusion of the non-valence configuration arising from
quark-pair creation is mandatory in order to ensure that the physical form
factors are independent of the recoiling direction. The main feature of the
non-valence contribution is discussed.
