  Viewing gravitational energy-momentum $p_G^\mu$ as equal by observation, but
different in essence from inertial energy-momentum $p_I^\mu$ naturally leads to
the gauge theory of volume-preserving diffeormorphisms of an inner Minkowski
space ${\bf M}^{\sl 4}$. To extract its physical content the full gauge group
is reduced to its Poincar\'e subgroup. The respective Poincar\'e gauge fields,
field strengths and Poincar\'e-covariant field equations are obtained and
point-particle source currents are derived. The resulting set of non-linear
field equations coupled to point matter is solved in first order resulting in
Lienard-Wiechert-like potentials for the Poincar\'e fields. After numerical
identification of gravitational and inertial energy-momentum Newton's inverse
square law for gravity in the static non-relativistic limit is recovered. The
Weak Equivalence Principle in this approximation is proven to be valid and
spacetime geometry in the presence of Poincar\'e fields is shown to be curved.
Finally, the gravitational radiation of an accelerated point particle is
calulated.
