Although the plugin works, it doesn't seem to be quite right. When using the category option to create your own styling the text colour is only implemented on the X (for delete this message) all other text still appears in black.
(It would be helpful if all the information for that category were represented when you edit instead of having to completely re-enter it).
The image to go with the message doesn't appear at all even if one of the provided images is used.
Would be useful if it were possible to style in CSS or provide styling information in css format. This would also allow the use of transparency.