HTML Message

I have a BO to create an email message. This BO has an Message attribute (Plain Text, HTML format).

When the user is finished typing his email I run a rule:

Notification.HTMLMessage=BO.HTMLMessage

The problem is that the HTMLMessage of a Notification is a Document type.

How can I let the user type HTML text and send it with an notification??

Nevermind, I found it already.
Setting the Notification.Message to HTML format solved it.