How can layout XML files be registered for the frontend and adminhtml areas?
In Magento, you may register a new Layout XML file with layout updates by adding this piece of XML to your module config.xml
<layout> <updates> <anyuniquename> <file>nv/homelayout.xml</file> </anyuniquename> </updates> </layout>
If you need the layout file to apply to the Magento frontend, you’ll need to add to the section <frontend> of your config.xml file. If you want it to apply to the Magento backend, you need to add to the section <adminhtml>, and if you the layout file to apply both to the frontend and to the backend, you may add it to the <global> section.