getting polyhedral data into openfoam

I have finally created a polyhedral cell in VTK format version 5.0 (wow!)
but now I am trying to figure out how to get this into openFoam format?
The vtkUnstructuredToFoam does not work on the modern VTK files.
I am guessing that converting to prostar (starccm?) format is the best bet,
since converters to/from openfoam already exist for that. Any suggestions?