Thanks OKH for your reply.
I guess I can manage to edit files, but I need to know filename and where to find these files.
Sorry if this is a stupid question, but please guide me where to look (path / filename).
Thank you in advance!
Best regards,
Larz2
Maybe, if you could provide some more information about the scope of your project and how you intend to use the pricing, it would provide a strong case for implementing the feature with a nice interface... 
ok
The idea is to make my own library with furniture to use for exhibitions, so clients can design an exhibition stand and know the total price for buying or renting the furnitures. ok
