Bug while saving pdf with rich text field?

Hi,
I think there is a bug saving a pdf with a rich text field. I dynamically changed the rawValue of the node representing a rich text field. The new value appears in the pdf document. But after saving and opening the saved document, the rich text field has its default value. If I use a text field with plain text, everything is working.
The only way how this works with a rich text field is typing any charakter in the field. Just a simple "return" is enough. I think that after hitting any key a special event is fired, so the text field keeps its value also in the saved document. Thats why I've tried to fire a change event manually. But with no success.

Is this a bug or is there a special way to set the value of rich text fields?