account_payment_sequence.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data noupdate="1">
        <record forcecreate="1" id="seq_type_rec_payment_order" model="ir.sequence.type">
            <field name="name">Receivable payment order</field>
            <field name="code">rec.payment.order</field>
        </record>

        <record forcecreate="1" id="seq_rec_payment_order" model="ir.sequence">
            <field name="name">Receivable payment order</field>
            <field name="code">rec.payment.order</field>
            <field eval="3" name="padding"/>
            <field name="prefix">%(year)s/</field>
        </record>
    </data>
</openerp>