View file Universal billing/plugins/payment/classes/Payment_Template.php

<?php 

class Payment_Template
{
    protected $vars = array();
    public $tpl_patch = 'tpl/';
    
    public function __construct() {
        
    }
    
    public function assign($varname, $value)
    {
        $this->vars[$varname] = $value;
        return true;
    }

    /*
    * Генерируем шаблон
    */
    public function getTemplate($tpl_file) 
    {
        // Помещаем переменные в форму
        extract($this->vars);
        
        if (is_file(TPL . $this->tpl_patch . $tpl_file . '.tpl.php')) {
            include TPL . $this->tpl_patch . $tpl_file . '.tpl.php';
        } else {
            return array('error' => __('Не удалось загрузить форму: ') . $tpl_file);
        }
    }
    
    public function display($tpl_file = 'document') 
    {
        return $this->getTemplate($tpl_file);
    }
}