  Models of asymmetric dark matter (ADM) seek to explain the apparent
coincidence between the present-day mass densities of visible and dark matter,
$\Omega_{\DM} \simeq 5\Omega_{\VM}$. However, most ADM models only relate the
number densities of visible and dark matter without motivating the similar
particle masses. We expand upon a recent work that obtained a natural mass
relationship in a mirror matter ADM model with two Higgs doublets in each
sector, by looking to implement dark electroweak baryogenesis as the means of
asymmetry generation. We explore two aspects of the mechanism: the nature of
the dark electroweak phase transition, and the transfer of particle asymmetries
between the sectors by the use of portal interactions. We find that both
aspects can be implemented successfully for various regions of the parameter
space. We also analyse one portal interaction -- the neutron portal -- in
greater detail, in order to satisfy the observational constraints on dark
radiation.
