[Zope-dev] How to use the PropertySheets-Class

For serveral reasons I want to implement propertysheets without using explicitly a ZClass. I found the PropertySheets.py - Module and played around with it but without good results. If I define something like ' propertysheets = PropertySheets() ' in my class, I'm able to add PropertySheets in the url or in the __init__ - Method of my class (self.propertysheet.addPropertySheet(self.mysheet)) but if i want to 'manage' this sheet, I get a permission defnied. So, my question: has anybody a small and basic implementation of the PropertySheets-Class with serveral propertysheets from wich I can learn ? Thanks, Martin