Since I pigheadedly wanted to install them anyway, what I ended up doing is using a hacksaw to cut off (1) the balls on the ends of my levers, and (2) about 1/4 inch off the ends of the handlebars. I bolted on the clamps right below the crossbar on either side. Once you've cut the lever balls off, the left handguard can be bolted on, although you'll need to twist the mirror mount backwards a bit to get the handguard to actually cover the clutch lever:
To get the right handguard on, you need to rotate the right mirror mount/brake reservoir, otherwise the bolt on the back of the reservoir will be in the way:
Assuming it is ok for the reservoir to be tilted like this...
Here are a couple other pics (sorry for the lousy quality, my phone's camera is kind of a joke):
As an aside, I should mention that the stock bars are really kind of awful. Therefore, I think I'm going to end up buying some aftermarket handlebars where the handguards can bolt on with no mods required... I've read -- and seen a picture! -- of Renthal 7/8 bars with the Moose handguards on, so I may just go with those.
Update: Got Renthal 7/8 CR high bend bars, and the Moose guards went on just fine. (Actually, one of the screws became cross-threaded, which sucked, but that isn't Renthal's fault...) Here's a pic:
