Stumble toolbar

you know the grey stumble toolbar that is visible on the very top of a blog or website when you like from a su.pr url?   I can't get that to work on my site, and the stumbleupon forums haven't been very helpful. I was wondering if it was because I was using the su.pr plugin for wordpress.  I configured it for custom URLs, but also installed the javascript that is s'posed to offer the grey toolbar, but no luck. Any ideas?