i dont know why you cant create the PS-Object with your approach.
However, I solved the same requirement as follows. I assigned a abstract class to the PS class with the abstract operations. The abstract operations are invoke in the state machine at the particular states:
In the model where the library is imported, the abstract operations are overwritten with the specific class:
Since i get also the PS-State class from the import, i can just create it with the PersistentStateAdapater: