well i succeed to add my own total row for cart:
- i created my own class in core / mage/ sales / model / quote / address / total / ecotax.php
- i added markups in core / sales / etc / system.xml and core / sales / etc / config.xml to display it in the admin section and in the total rows for my cart
However, it doesn’t appear in order view.
It seems that i have to store the amount in the database: in this way, i created an attribute and linked it to order through entity_attribute table.
How can i store that informaiton when order is placed ?
thanks for any help