Weston, my testing shows that your solution still works. However, the avatar may need to be closer to the box than before. And it might work better if the box has a sit target (based on what was said above; I didn't test this).
BTW, there was a change to sitting that probably affects this behavior. I'll post the JIRA entry when I find it, but if you look at the blog for the next server release, you'll see that they're backing out this particular change -- so things should go back to more like they were before.
Confused yet? No? Well, just wait.
