  Linear time-distance helioseismic inversions are carried out using several
filtering schemes to determine vector flow velocities within two
$\sim100^2\,{\rm Mm^2}\times 20\,{\rm Mm}$ realistic magnetohydrodynamic
sunspot simulations of 25~hr. One simulation domain contains a model of a full
sunspot (i.e. one with both an umbra and penumbra), while the other contains a
pore (i.e. a spot without a penumbra). The goal is to test current helioseismic
methods using these state-of-the-art simulations of magnetic structures. We
find that horizontal flow correlations between inversion and simulation flow
maps are reasonably high ($\sim0.5$--0.8) in the upper 3~Mm at distances
exceeding 25--30~Mm from spot center, but are substantially lower at smaller
distances and larger depths. Inversions of forward-modeled travel times
consistently outperform those of our measured travel times in terms of
horizontal flow correlations, suggesting that our inability to recover flow
structure near these active regions is largely due to the fact that we are
unable to accurately measure travel times near strong magnetic features. In
many cases the velocity amplitudes from the inversions underestimate those of
the simulations by up to 50\%, possibly indicating nonlinearity of the forward
problem. In every case, we find that our inversions are unable to recover the
vertical flow structure of the simulations at any depth.
