My plugin will be adding this functionality in the next release (in beta now). If you want, you can download the beta at http://www.johnpbloch.com/custom-post-permalinks.zip
There are still known bugs in that beta version, though. I don’t have the time to give you a proper answer on here at the moment (it’s a pretty complicated fix); we’ll see if I release the new version before I get around to it… 😉
EDIT
My plugin is now in its release candidate phase. If there are no more bugs found by Thursday morning, I’ll release it. I don’t anticipate this happening, though. You can find the release candidate at the same url as above. I think that should solve your problem. Taxonomy tags are the taxonomy’s name (as registered. This may be different from the label).