Add attachment to transactional email in magento
devm.com.np
<?php
$mailer 
Mage::getModel('core/email_template_mailer');
$emailInfo Mage::getModel('core/email_info');
$emailInfo->addTo($customerEmail$customerName);

$mailer->addEmailInfo($emailInfo);

$mailer->setSender(Mage::getStoreConfig(self::XML_PATH_EMAIL_IDENTITY$storeId));
$mailer->setStoreId($storeId);
$mailer->setTemplateId($templateId);
$mailer->setTemplateParams(array(
        
'object'        => $object,
    )
);

$emailTemplate Mage::getModel('core/email_template');
        
$xml '';

$mail $emailTemplate->getMail();

$attachment $mail->createAttachment($xml);

$attachment->type        'text/xml';
$attachment->disposition Zend_Mime::DISPOSITION_INLINE;
$attachment->encoding    Zend_Mime::ENCODING_BASE64;
$attachment->filename 'test.xml';

try{
    
$emailTemplate->setDesignConfig(array('area' => 'frontend''store' => $mailer->getStoreId()))
        ->
sendTransactional(
        
$mailer->getTemplateId(),
        
$mailer->getSender(),
        
$emailInfo->getToEmails(),
        
$emailInfo->getToNames(),
        
$mailer->getTemplateParams(),
        
$mailer->getStoreId()
    );
}
catch(
Exception $e)
{
    
Mage::log($e->getMessage(), null'Error.log');
}
?>