Override community plugin model - Magento 1.9

Question

Hi guys I have a plugin that I need to amend!

The file I need to change is: /app/code/local/Magestore/Pdfinvoiceplus/Model/Sales/Order/Invoice.php

Here are my plugin files:

/config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Company_InvoiceEmail>
            <version>0.0.1</version>
        </Company_InvoiceEmail>
    </modules>
    <global>
        <models>
            <invoiceemail>
                <class>Company_InvoiceEmail_Model</class>
            </invoiceemail>
            <magestore_pdfinvoiceplus>
                <rewrite>
                     <sales_order_invoice>Company_InvoiceEmail_Model_Sales_Order_Invoice</sales_order_invoice>
                 </rewrite>
             </magestore_pdfinvoiceplus>
        </models>
    </global>
</config>

/app/code/local/Company/InvoiceEmail/Model/Sales/Order/Invoice.php

class Company_InvoiceEmail_Model_Sales_Order_Invoice extends Magestore_Pdfinvoiceplus_Model_Sales_Order_Invoice
{
...
}

Can someone point me in the right direction as to why my module isn't overriding this class?

Thanks!

EDIT Original plugin snippet:

<global>
        <models>
            <pdfinvoiceplus>
                <class>Magestore_Pdfinvoiceplus_Model</class>
                <resourceModel>pdfinvoiceplus_mysql4</resourceModel>
            </pdfinvoiceplus>
            <sales>
                <rewrite>
                    <order>Magestore_Pdfinvoiceplus_Model_Sales_Order</order>
                    <order_invoice>Magestore_Pdfinvoiceplus_Model_Sales_Order_Invoice</order_invoice>
                    <order_creditmemo>Magestore_Pdfinvoiceplus_Model_Sales_Order_Creditmemo</order_creditmemo>
                </rewrite>
            </sales>
        </models>
</global>

Answer 1

AFAIK You have to write below way to rewrite this module

<?xml version="1.0"?>
<config>
<modules>
    <Company_InvoiceEmail>
        <version>0.0.1</version>
    </Company_InvoiceEmail>
</modules>
<global>
    <models>
        <invoiceemail>
            <class>Company_InvoiceEmail_Model</class>
        </invoiceemail>
        <pdfinvoiceplus><!--Change this node-->
            <rewrite>
                 <sales_order_invoice>Company_InvoiceEmail_Model_Sales_Order_Invoice</sales_order_invoice>
             </rewrite>
         </pdfinvoiceplus>
    </models>
</global>
</config>

create a new file in etc\modules file name would be Company_InvoiceEmail.xml

<config>
    <modules>
        <Company_InvoiceEmail>
            <active>true</active>
            <codePool>local</codePool>
            <depends>
                <Magestore_Pdfinvoiceplus/>
            </depends>
        </Company_InvoiceEmail>
    </modules>
</config>