[Zope] Properties in a propertysheets unreachable

In a ZClass you can define a couple of propertysheets and stick properties in there that can be access from the instance like a "normal" property. # Explicit way print context.propertysheets.get('myproperties').getProperty('age') # ...or simpler: print context.age I'm developing a python product and now I can't reach my properties from my templates. I must use the explicity way to get to the values. # This works <div tal:replace="python:here.propertysheets.get('properties').getProperty('name_cookiekey')"></div> # This doesn't (which used to work when the product was a ZCLass) <div tal:replace="python:here.name_cookiekey"></div> What do I need to do to get simple access to the properties in the propertysheets I have? Peter