@@get_viewer_role_info

Greetings,

I'm trying to call zope3/five registered view in the subject of this email but 
it appears to not be registered for all types of Silva objects.

As a manager I have access to call this view directly from my browser, e.g. 
http://mysite.com/silva/folder/document/@@get_viewer_role_info

This works for "Silva Document", "Silva Folder" and "Silva Publication".  
However, it does not work for "Silva Document Version" nor "Silva Article".  
I'm trying to figure out why, but coming up short.  This view is registered  
for="Products.Silva.interfaces.ISilvaObject", so I don't know why it's not 
working.

The versions I'm using are:
Silva,SilvaDocument 1.5.3
SilvaNewsNetwork 2.1.1
Five 1.2.6
Zope 2.8.6

Cheers,
Andy