You can only do it from a clas diagram view. This transformation seems
only to be working at class diagram diagram level.
btw, you can recreate a class diagram from your model using model to model
transformation ant then customize EMF serialization to create activity and
state diagram diagram. The problem is that during these transformation
stages you are going to loose model information and you will never get any
graphical representation (e.g. the graphical presentation is lost only the
model is transformable)
If you have an existing model did you ever consider to manually recreate
it ? I mean that even if it is 10 or 50 days of work, it would always be
more accurate information than trying to push an elephant in a mouse hole
!!