Validation errors in "Techniques for providing useful text alternatives" page

Hello, 
 
I used some techniques from "Techniques for providing useful text alternatives" page however the W3C validation service shows the following errors: 
 
- Error 1: Attribute role not allowed on element figure at this point.
<figure role="group">
-- Role is a solution to provide a programmatically determinable relationship between the image and its description until: http://www.w3.org/TR/html-alt-techniques/#haee ( http://www.w3.org/TR/html-alt-techniques/ )
Also upon the page http://www.w3.org/TR/wai-aria/roles#group Authors SHOULD use a group to form logical collection of items in a widget ( http://www.w3.org/TR/wai-aria/terms#def_widget ) such as children in a tree widget forming a collection of siblings in a hierarchy, or a collection of items having the same container in a directory. 
Is role supported or not for the figure element?
 
- Error 2: Element p not allowed as child of element figure in this context. (Suppressing further errors from this subtree.)
<figure role="group">
<img src="webcam1.jpg" alt="Sopwith house weather cam.">
<figcaption>View from the top of Sopwith house </figcaption>
<p>This image is updated every hour.</p>
</figure>
-- Sometimes there is a note <p> or table and it is not always usable to have them all with the image before or after the <figcaption> 
so what to do? A similar example exists on http://www.w3.org/TR/html-alt-techniques/#hbh 
 
Thank you,
Rabab