eiru_service/wizard/commission_wizard.xml

<?xml version="1.0"?>
<openerp>
    <data>
        <record model="ir.ui.view" id="project_service_commission_wizard_view">
            <field name="name">project.service.commission.wizard.form</field>
            <field name="model">project.service.commission.wizard</field>
            <field name="arch" type="xml">
                <form string="Commission">
                    <group>
                        <group>
                            <field name='task_id' string="Tarea" invisible="1"/>
                            <field name='activity_id' string="Tarea"/>    
                        </group>
                        <group>
                            <field name='user_id' string="Funcionario"/>
                            <field name='amount' string="Valor de la comisión"/>    
                        </group>                                                
                    </group>
                <footer>
                    <button name="add_commision" type="object" class="oe_highlight" string="Aceptar"/>
                </footer>
                </form>
            </field>
        </record>

        <record model="ir.actions.act_window" id="action_commision_add">
            <field name="name">Asignar comisión</field>
            <field name="res_model">project.service.commission.wizard</field>
            <field name="view_type">form</field>
            <field name="view_mode">form</field>
            <field name="target">new</field>
        </record>
    </data>
</openerp>