standard openerp only allows a link from a form view not a tree view. the alternative is to add an action button on the tree view - see inwards goods picking for an example

For the button there's some things that i don't know how to do (sorry i'm starting in developping module) :
 the name="something_there" is related to a function in my module.py file ? But how i can send the client in the invoice which is related to the invoice_id and partner_id actual line ?