I'm newbie in here, so my question is how can I add new relational fields One2many inside my existing inherit model??
Are you not able to do it by defining new fields in the inherited model like this
one2many_field = fields.One2many(codmodel, inverse_name)
many2many_field = fields.Many2many(comodel)
Would have been nicer if you could add more information about the problem you're facing.