  We present measurements of the polarization-transfer components in the
$^2$H$(\vec e,e'\vec p)$ reaction, covering a previously unexplored kinematic
region with large positive (anti-parallel) missing momentum, $p_{\rm miss}$, up
to 220 MeV$/c$, and $Q^2=0.65$ $({\rm GeV}/c)^2$. These measurements, performed
at the Mainz Microtron (MAMI), were motivated by theoretical calculations which
predict small final-state interaction (FSI) effects in these kinematics, making
them favorable for searching for medium modifications of bound nucleons in
nuclei. We find in this kinematic region that the measured
polarization-transfer components $P_x$ and $P_z$ and their ratio agree with the
theoretical calculations, which use free-proton form factors. Using this, we
establish upper limits on possible medium effects that modify the bound
proton's form factor ratio $G_E/G_M$ at the level of a few percent. We also
compare the measured polarization-transfer components and their ratio for $^2$H
to those of a free (moving) proton. We find that the universal behavior of
$^2$H, $^4$He and $^{12}$C in the double ratio
$\frac{(P_x/P_z)^A}{(P_x/P_z)^{^1\rm H}}$ is maintained in the positive
missing-momentum region.
