In my experience, especially on road frames, it isn't necessarily the weight on the frame that will outright break it, but the repeated flexing which causes aluminum to fatigue and crack (especially around the bottom bracket). So more load = more flex, more often... eventually, yes, it is going to fail. Whether that happens on your tour or not is kind of a gamble... I've never ridden the exact frame you are talking about, so this is just general knowledge. I have ridden a few flexy aluminum frames that made me nervous... one of which was an old-school mtb frame that nearly broke in half about 15 seconds after getting off of a pretty technical trail (lucky!). Flex in a steel frame is GOOD. Flex in an aluminum frame is NOT SO GOOD.

That said, people have crossed the US quite successfully on all manner of machines that look like they could fall apart at any moment. Many will tell you that a steel touring frame is the way to go, since if it cracks it can be easily welded anywhere. You don't say where you are planning on touring, but if you are in the US, it is not quite as much of a problem to get a few TIG welds done on the road in the event of a disaster.

I would look at the forums here and check out Ken Kifer's excellent pages to see what you really need to take, and travel as light as possible... or pull a trailer: there is little worse in the bike handling department than a whippy frame with lots of gear strapped to it.