Webdesk search knowledge base how?

I can't find a way to search the knowledge base from within webdesk in the same way you can in the admin console using the search knowledge base option.

I don't need to search the knowledge base during the logging of an Incident, but i need to to search back through old incidents via the webdesk search for text in Incidents exactly as I can in the admin console.

Any Ideas info on this is very vague.

Thanks