Tensor force in HQET and the semileptonic B decay to excited vector mesons D(3 2- , 1- )

We extend the formalism of Leibovich, Ligeti, Steward and Wise for the ${1 \over 2}^- \to {3 \over 2}^+$ form factors to the ${1 \over 2}^- \to {3 \over 2}^-$ transitions in the $1/m_Q$ expansion of Heavy Quark Effective Theory. We show that the corresponding subleading $1/m_Q$ magnetic coupling at zero recoil is related to the tensor force that describes the mixing between $D^* (\textstyle{{3 \over 2}^-, 1^-})$ and $D^* (\textstyle{{1 \over 2}^-, 1^-})$. We point out some subtleties that appear in this respect in HQET.