  The Kaluza-Klein reduction of the 3d gravitational Chern-Simons term to a 2d
theory is equivalent to a Poisson-sigma model with fourdimensional target space
and degenerate Poisson tensor of rank 2. Thus two constants of motion (Casimir
functions) exist, namely charge and energy. The application of well-known
methods developed in the framework of first order gravity allows to construct
all classical solutions straightforwardly and to discuss their global
structure. For a certain fine tuning of the values of the constants of motion
the solutions of hep-th/0305117 are reproduced. Possible generalizations are
pointed out.
