odoo/addons/account_followup/account_followup_data.xml

<?xml version="1.0"?>
<openerp>
    <!-- Mail template is done in a NOUPDATE block
         so users can freely customize/delete them -->
    <data noupdate="1">

        <!--Email template -->
        <record id="email_template_account_followup" model="email.template">
            <field name="name">Followup of outstanding accounts</field>
            <field name="email_from">${object.user_id.email or ''}</field>
            <field name="subject">${object.company_id.name} Followup</field>
            <field name="email_to">${object.email}</field>
            <field name="lang">${object.lang}</field>
            <field name="model_id" ref="base.model_res_partner"/>
            <field name="auto_delete" eval="True"/>
            <field name="body_html"><![CDATA[
<div style="font-family: 'Lucica Grande', Ubuntu, Arial, Verdana, sans-serif; font-size: 12px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 255); ">
    
    <p>Hello${object.name and ' ' or ''},</p>
    
    <p>We see in our books that some accounts are not settled yet:</p>
    

    <table>

        <tr>
            <td>Debit</td>
            <td>Credit</td>
            <td>Reference</td>
        </tr>

        
% for aml in object.accountmoveline_ids : 

<tr>
<td>
${aml.debit}
</td>
<td>
${aml.credit}
</td>
<td>
${aml.ref}
</td>
</tr>
% endfor
</table>

    

    <p style="border-left: 1px solid #8e0000; margin-left: 30px;">
       &nbsp;&nbsp;<strong>REFERENCES</strong><br />
       &nbsp;&nbsp;Order number: <strong>${object.name}</strong><br />
       &nbsp;&nbsp;Your contact: <a href="mailto:${object.user_id.email or ''}?subject=Order%20${object.name}">${object.user_id.name}</a>
    </p>
    <br/>
</div>
            ]]></field>
        </record>
    </data>
</openerp>