I tried adding it but when I click the new little icon, I get an error (“For some reason, that story doesn’t seem to be in our system. We’re already on the case, trying to figure out what went wrong.”). Funny thing is that my button’s link is laid out exactly the same as those on other sites.
It looks like the url needs to be urlencoded, which I think is new for Sociable? I hacked that into my copy of the plugin, but to no avail.