Registry actions in Custom updates should be able to detect x64 system and then 'Translate' Registry Keys to the "Wow6432Node" if asked by the user.
Comments: Are you trying to avoid or use registry redirection? Have you read [this](http://msdn.microsoft.com/en-us/library/windows/desktop/aa384253(v=vs.85).aspx)? I'd recommend using a script to accomplish this, or setting up two different custom updates, one targeted for x64 and one targeted for x86 systems.
Comments: Are you trying to avoid or use registry redirection? Have you read [this](http://msdn.microsoft.com/en-us/library/windows/desktop/aa384253(v=vs.85).aspx)? I'd recommend using a script to accomplish this, or setting up two different custom updates, one targeted for x64 and one targeted for x86 systems.