Assign a custom popup.phtml file through a custom extension - magento

Question

Building a custom extension and need to load a new popup.phtml file so we can place our own code into it.
Ive already tried adding it as a package, but I want to avoid this so wondering if theres a way to add this/link to this using an xml layout file for example?
So in short, when a user clicks on the "Track Shipment" link in either the end user account, or the admin clicks the link from Sales > Shipments > View it will load my popup.phtml file and not the default one.

Answer 1

I've managed to solve this so here's how I managed to to it just in case it helps anyone else out :)
First of all in the app/etc/modules you'll need to create a file, lets call it Vendor_Module.xml and in there, we'll put the code;
<?xml version="1.0" encoding="UTF-8"?>
<config>
<modules>
<Vendor_Module>
<active>true</active>
<codePool>community</codePool>
</Vendor_Module>
</modules>
</config>
Then in app/community/Vendor/Module/etc/config.xml I added the following;
<?xml version="1.0"?>
<config>
<modules>
<Vendor_Module>
<version>1.0.0</version>
</Vendor_Module>
</modules>
<frontend>
<layout>
<updates>
<Vendor_Module_layout module="Vendor_Module">
<file>vendor_module.xml</file>
</Vendor_Module_layout>
</updates>
</layout>
</frontend>
</config>
In app/design/admin/default/default/layout I created vendor_module.xml and added the following code;
<?xml version="1.0"?>
<shipping_tracking_popup translate="label">
<label>Shipment Tracking Popup</label>
<reference name="root">
<action method="setTemplate"><template>page/popuper.phtml</template></action>
</reference>
<reference name="content">
<block type="shipping/tracking_popup" name="shipping.tracking.popup" template="shipping/tracking/popuper.phtml" />
</reference>
</shipping_tracking_popup>
In app/design/frontend/base/default/layout I created another vendor_module.xml file and added the code;
<?xml version="1.0"?>
<layout>
<shipping_tracking_popup>
<reference name="content">
<block type="shipping/tracking_popup" name="shipping.tracking.popup" template="Vendor/shipping/tracking/popup.phtml" />
</reference>
</shipping_tracking_popup>
</layout>
Finally, in app/design/frontend/base/default/template/Vendor/shipping/tracking I created a new file called popup.phtml and then added my own required code that I wanted displayed here. The following code is just example code that will add some text and a close button.
<div class="page-title title-buttons">
<h1><?php echo $this->__('Tracking Information'); ?></h1>
<button class="button" onclick="window.close(); window.opener.focus();"><span><span><?php echo $this->__('Close Window') ?></span></span></button>
</div>
<!-- Add Your Stuff Here -->
<div class="buttons-set">
<button type="button" title="<?php echo Mage::helper('core')->quoteEscape($this->__('Close Window')) ?>" class="button" onclick="window.close(); window.opener.focus();"><span><span><?php echo $this->__('Close Window') ?></span></span></button>
</div>
Thats it, hope it helps!