[Seaside] OmniBase question ref. model changes

[Dmitry Dorofeev]

Hi all,

I have an OnniBase with some objects of class User and class Student stored.
Student is inherited from User.

I hacked a class User and added instance variable lastLoggedIn and accessors.
Now objects of class Student taken from OmniBase are messed up, i.e. values
of instance variables get wrong. Seems they are just get shifted.

Is there a safe way to change model for objects in the OmniBase database?
Online docs are not so expressive :-(

Thanks,
-Dmitry.