passing html with Rules in Drupal 7

There is a problem when using Rules in Drupal 7. Something I used to be able to do in D6.
I have a node field that is of type long text and is filtered Full HTML. I set up a rule that after a certain event it should populate that field with a certain html snippet. like <img src="http://mydrupalsite.com/images/image.png">
I put the condition for the entity to contain that field. I think I did everything by the book but I cannot make that filed to contain html. It is empty. I don't know what I'm doing wrong. Please advise.
Thank you.