Block specific country code TLDs

In the FortiOS 4.0 codebase we could implement a Web Rating Override that would allow us to reclassify specific country code top level domains, and thus block them (by assigning the URL an override of Security Risk -> Malicious Websites, or the like). After upgrading to the 5.0 code base (running 5.2.6 at this time) I find I can no longer add just a country code TLD in the same way.  Attempts to do so result in "Please enter a valid URL" in the GUI and the new entry is rejected.   Even when trying to use wildcards.

So I'd like to know if anyone has a way to do this now in FortiOS 5.  It sure doesn't seem like doing so via a Web Rating Override is an option anymore.  

Here's an example: say I want to block all internal attempts to access .ru websites.   Yes, all domains that end in .ru.  Any guidance on how to go about that now?

Thanks.