Hello I have my rwizard with a field Many2one for product.product, after ther is my function that is in the same idea like the documentation, All is ok, the Wizard load ok, show the selection widget and make the submit, but y dont get my report on my screen.

Somehting interesting is that if I load the report by a url, this works pefectly

Here is the code of all:

wizard.py

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

from openerp import models, fields, api

class Wizard(models.AbstractModel):
    _name = 'velfasa.wizard'
    product_id = fields.Many2one('product.product', string='Producto', widget='selection', store=False)

    @api.multi
    def render_html(self, data=None):
        report_obj = self.env['report']
        report = report_obj._get_report_from_name('velfasa.utilities')
        docargs = {
            'doc_ids' : self._ids,
            'doc_model' : report.model,
            'docs' : self.product_id,
        }
        return report_obj.render('velfasa.utilities', docargs)

reports.xml

<openerp>
<data>
    <report
        id="report_sale_utilities"
        model="product.product"
        string="Reporte de utilidad"
        name="velfasa.utilities"
        file="velfasa.utilities"
        report_type="qweb-pdf" />

    <template id="utilities">
        <t t-call="report.html_container">
            <t t-foreach="docs" t-as="doc">
                <t t-call="report.external_layout">
                    <div class="page">
                        <p><h2>Producto:</h2> <span t-field="doc.name"/></p>
                        <separator/>
                    </div>
                </t>
            </t>
        </t>
    </template>

</data>
</openerp>

sale.xml

<?xml version="1.0" encoding="UTF-8"?>
 <openerp>
    <data>
        <menuitem id="sale_reports" name="Informes" parent="base.menu_base_partner" />

        <menuitem id="sale_reports_utilities" name="Utilidades" parent="sale_reports"
                 action="launch_vel_utilities_wizard"  />

        <record model="ir.ui.view" id="wizard_form_view">
            <field name="name">wizard.form</field>
            <field name="model">velfasa.wizard</field>
            <field name="arch" type="xml">
                <form string="Informe de utilidades">
                    <group>
                        <field name="product_id" widget="selection"/>
                    </group>
                    <footer>
                        <button name="render_html" type="object" string="Imprimir" class="oe_highlight" target="_blank" />
                        <button special="cancel" string="Cancelar" />
                    </footer>
                </form>
            </field>
        </record>

        <act_window id="launch_vel_utilities_wizard"
                    name="Informe de utilidades"
                    src_model="product.product"
                    res_model="velfasa.wizard"
                    view_mode="form"
                    target="new"/>
    </data>
</openerp>