  We construct part of the superspace vielbein and tensor gauge field in terms
of the component fields of 11-dimensional on-shell supergravity. The result can
be utilized to describe supermembranes and corresponding matrix models for
Dirichlet particles in nontrivial supergravity backgrounds to second order in
anticommuting coordinates. We exhibit the kappa-invariance of the corresponding
supermembrane action, which at this order holds for unrestricted supergravity
backgrounds, the supersymmetry covariance and the resulting surface terms in
the action.
