eiru_contract_vendor/models/eiru_contract.py

# -*- coding: utf-8 -*-

from openerp import api, models, fields


class account_analytic_account(models.Model):
    _inherit = "account.analytic.account"

    employee_id = fields.Many2one(string='Cobrador', related="partner_id.employee_id")

    def _prepare_invoice_data(self, cr, uid, contract, context=None):
        context = context or {}
        invoice = super(account_analytic_account, self)._prepare_invoice_data(
            cr, uid, contract, context=context)
        invoice.update({
            'employee_id': contract.employee_id})
        return invoice