account-financial-tools/account_credit_control_dunning_fees/view/policy_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
  <data>
    <record id="add_dunning_fees_on_policy" model="ir.ui.view">
      <field name="name">add dunning fees on policy</field>
      <field name="model">credit.control.policy</field>
      <field name="inherit_id" ref="account_credit_control.credit_control_policy_form" />
      <field name="arch" type="xml">
        <page string="Mail and reporting" position="after">
          <page string="Fees">
            <group>
              <group>
                <field name="dunning_fixed_amount"/>
                <field name="dunning_product_id"
                       attrs="{'required': [('dunning_fixed_amount', '!=', False)]}"/>
                <field name="dunning_currency_id"
                       attrs="{'required': [('dunning_fixed_amount', '!=', False)]}"/>
              </group>
            </group>
          </page>
        </page>
      </field>
    </record>

  </data>
</openerp>