Protege on MacOS 10.7 and 10.8: OWLViz broken; no version of graphviz seems to work

Only on my older Mac (OSX 10.6) does the Protege plugin OWLViz work;   in
OSX 10.7 and 10.8, no matter what version of graphviz is installed (using
Homebrew),  OwlViz does not work.

The documentation does not seem to help here.  The CompatibleWith  property
needs to be extended and linked to external dependencies:

1.  Operating System type
2.  Operating system version
3.  Java version
4.  External application version (graphviz, etc.)

http://protegewiki.stanford.edu/index.php?title=Property:Compatible_with&from=Matrix+1.0.15#SMWResults

Has anyone else had the same problem?  Suggestions?

Thank you

Rafael Richards MD MS