If the point of the amendment is to say “compliant with Kyoto—as amended from time to time” and it adds “any successor agreement”, which would imply that it was a successor within the United Nations process—in other words, as opposed to outside it—then some form of words along those lines might work. That's provided we're explicit about the United Nations process and are recognizing that there will be something post-2012 that won't be called Kyoto, of course.
On March 27th, 2007. See this statement in context.