[marco_kellershoff]

You don't need a product xml. All you need is an extension and a product. The extension will show up without a product.xml. Once it shows up you can add a product for that extension manually in the AdminCP.

The extension is basically a .php file inside the packages/yourextensionname/api/ directory.

PHP Code:

<?php
class wpHeaderFooter_Api_Options extends vB_Api_Extensions
{
    public $product = 'wpHeaderFooter';
    public $version = '1.0.0';
    public $developer = 'foo';
    public $title = 'WordPress Integration Extension';
    public $minver = '5.0.4';
    public $maxver = '5.0.4';
    public $infourl = '';
    public $checkurl = '';
    public $AutoInstall = 0;
    public $extensionOrder = 10;
    
    public function wpHeader(){
        define('ROOT_DIR',str_replace('\\\\', '/', realpath(dirname(__FILE__))).'/'); #Get real path for root dir ---linux and windows
        require_once(ROOT_DIR.'../beta/wp-blog-header.php'); // get WordPress  
        get_header();
    }
    
    public function wpFooter(){
        define('ROOT_DIR',str_replace('\\\\', '/', realpath(dirname(__FILE__))).'/'); #Get real path for root dir ---linux and windows
        require_once(ROOT_DIR.'../beta/wp-blog-header.php'); // get WordPress  
        get_footer();
    }
}

Put this into packages/wpheaderfooter/api/options.php



Not tested, but should work.