User interfaces inTurbine

Hi all,

I run into a problem which I cannot solve by myself:

Console excerpt:

java.lang.ClassCastException: 
org.apache.turbine.services.security.torque.om.TurbineUser cannot be 
cast to (own User interface class which extends 
org.apache.turbine.om.security.User)

Is it wrong to use 
org.apache.turbine.services.security.torque.om.TurbineUser for User's 
base om classes? Because org.apache.turbine.om.security.User, is not 
mappable with instances of type 
org.apache.turbine.services.security.torque.om.TurbineUser.

I do not use fulcum user classes here because, as I see, Turbine has 
it's own user interface.

cheers,
Johannes