HTML in Mass mailer

How to change the limited text editor used for the mass mails body for an extended one that allow to change font size, insert embeded images, ... ???

administration/notifies.php

function getEmailMessage($sAction)

'body' => array(
'type' => 'textarea',
'name' => 'body',
'value' => $sBody,
'caption' => $sBodyC,
'required' => true,
'html' => 1,
'checker' => array (
'func' => 'length',
'params' => array(10,32000),
'error' => $sErrorC,

Edit:

'html' => 1,

To:

'html' => 2,

Not tested it

Thanks a lot okweb