George,
>     I would recommend using the params database object in some fashion, 
> it seems to be exactly meant for the purpose you are describing -- 
> collecting user-configurable data into an easily traversed and 
> manipulated container. just my $.02 EU

I'll try both ways however, just to have a better understanding of all 
possible mechanisms.

The reason I tend to view these user data differently from parameters is 
that, for me, parameters are more intended to represent configuration or 
tuning relative data, which are supposed to be maintained by the maker 
of the application. User data are volatile information, only valid for a 
given run. But I agree that maybe this is only phylosophical 
consideration ;-)

Thanks a lot anyway for sharing your experience and knowledge of ECJ.

Best regards

Eric