Email sent by the rule action: "Send Message with Message notify" is sent in plain text and I can see all the html tags.

Email sent by the rule action: "Send Message with Message notify" is sent in plain text and I can see all the html tags.

I see that the problem is the email headers, but I can send html emails with other modules, like webform with no problem.
I have enabled the mimemail module.

Headers:

Mime-Version: 	1.0
	Content-Transfer-Encoding: 	8Bit
	Content-Type: 	text/plain; charset="utf-8"
	X-Dinascanner-Information: 	DinaScanner. Filtro anti-Spam y anti-Virus
	X-Dinascanner-Id: 	39F51925783.658AC
	X-Dinascanner: 	Libre de Virus

This is what I see in the email: (part of the email body):

<div class="message-wrapper">
<div class="header">
<div class="logo"><a href="http://www.misite.com/es"><img src="http://www.misite.com/sites/default/files/logo-misite.png" alt="misite" title="misite" /></a></div>
<div class="thank-you">Thanks for your order</div>
</div>
<div class="body">
<p class="detail">
     Here are the details for your order <span class="order"><a href="http://www.misite.com/es/user/21/orders/16">#16</a></span>, placed on Jue, 05/23/2013 - 22:06
   </p>