account_invoice_line_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="view_invoice_line_form_uos" model="ir.ui.view">
            <field name="name">view_invoice_line_form_uos</field>
            <field name="model">account.invoice.line</field>
            <field name="inherit_id" ref="account.view_invoice_line_form"></field>
            <field name="arch" type="xml">
                <xpath expr="//form/group/group/div" position="after">
                    <label for="uom_qty" groups="product.group_uom"/>
                    <div groups="product.group_uom">
                        <field name="uom_qty" class="oe_inline"/>
                        <field name="uom_id" class="oe_inline"/>
                    </div>
                </xpath>
            </field>
        </record>
        <record id="invoice_form_uos" model="ir.ui.view">
            <field name="name">invoice_form_uos</field>
            <field name="model">account.invoice</field>
            <field name="inherit_id" ref="account.invoice_form"></field>
            <field name="arch" type="xml">
                <field name="uos_id" position="after">
                    <field name="uom_qty" groups="product.group_uom"/>
                    <field name="uom_id" groups="product.group_uom"/>
                </field>
            </field>
        </record>
    </data>
</openerp>