  We present a new implementation of the magnetic Doppler imaging technique,
which aims at self-consistent temperature and magnetic mapping of the surface
structures in cool active stars. Our magnetic imaging procedure is unique in
its capability to model individual spectral features in all four Stokes
parameters. We discuss performance and intrinsic limitations of the new
magnetic Doppler imaging method. A special emphasis is given to the
simultaneous modelling of the magnetically sensitive lines in the optical and
infrared regions and to combining information from both atomic and molecular
spectral features. These two techniques may, for the first time, give us a tool
to study magnetic fields in the starspot interiors.
