Burkhard,
It's the other way round - there is a SKP Importer for Archicad that can be downloaded from the Graphisoft site. The version I have tested is meant for version 11, I don't know if it works with 12. Models imported with it needed quite a lot of cleanup, but it is a nice way of creating custom doors and windows as SU hole-cutting components are imported as windows or doors (if they touch an edge) into Archicad.
Anssi