pos_buttons/views/account_voucher_button_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data> 
        <!-- Account Voucher Tree -->
        <record id="account_voucher_button_tree" model="ir.ui.view">
            <field name="name">pos_buttons.account.voucher.button.tree</field>
            <field name="model">account.voucher</field>
            <field name="inherit_id" ref="account_voucher.view_voucher_tree"/>
            <field name="arch" type="xml">
                <xpath expr='//tree[@string="Voucher Entries"]' position='attributes'>
                    <attribute name="create">false</attribute>
                </xpath>
            </field>
        </record>
        
        <!-- Customer: Account Voucher Form -->
        <record id="account_supplier_voucher_button_form" model="ir.ui.view">
            <field name="name">pos_buttons.account.voucher.button.form</field>
            <field name="model">account.voucher</field>
            <field name="inherit_id" ref="account_voucher.view_vendor_receipt_form"/>
            <field name="arch" type="xml">
                <xpath expr='//form[@string="Receipt"]' position='attributes'>
                    <attribute name="create">false</attribute>
                </xpath>
                <xpath expr='//form[@string="Receipt"]' position='attributes'>
                    <attribute name="edit">false</attribute>
                </xpath>
            </field>
        </record> 

        <!-- Supplier: Account Voucher Form -->
        <record id="account_supplier_voucher_button_form" model="ir.ui.view">
            <field name="name">pos_buttons.account.supplier.voucher.button.form</field>
            <field name="model">account.voucher</field>
            <field name="inherit_id" ref="account_voucher.view_vendor_payment_form"/>
            <field name="arch" type="xml">
                <xpath expr='//form[@string="Voucher Payment"]' position='attributes'>
                    <attribute name="create">false</attribute>
                </xpath>
                <xpath expr='//form[@string="Voucher Payment"]' position='attributes'>
                    <attribute name="edit">false</attribute>
                </xpath>
            </field>
        </record>   
    </data>
</openerp>