How do I upgrade from Windows 7 RC to Windows 7 RTM?

There is a technique described here which sounds like it might work to upgrade RC->RTM. Has anybody tried this?

Brandon LeBlanc on this Windows 7 Team blog post states you need to do clean install from the RC versions.

Brandon is the Windows Communications Manager at Microsoft

The How-To Geek has a write-up on exactly how to perform an upgrade from RC to RTM.

How to Upgrade the Windows 7 RC to RTM (Final Release) :: the How-To Geek

EDIT: FYI, in the linked article the How-To Geek explains exactly what build number you must specify in the cversion.ini file to make this way of upgrading work.