Thanks, but I'm aware of the Zcatalog section in the Zope book. I got the ZCatalog perfectly working with my ZClasses. However I'm building the next generation of our Zope based cms entirely with external products, leaving ZClasses behind. Documention including the developpers guide isn't any helpfull regarding the Zcatalog in this respect.
That is because there is nothing special for external products with respect to the ZCatalog: attributes and parameterless methods are indexed/put in the catalog's metadata row when the name agrees.
This general principle applies to everthing: Zope objects, ZClasses, external products ...
-- Dieter
What I overlooked was the fact that you have to define an acces method (as Alec Mitchell pointed out) for the fields in the dictionaries and use that as fieldnames in the indexes. Stupid of me, basic OOP, but I didn't know I could use methods as fields for the indexes. I have it now perfectly working. Henny