IIRC Quantum Leaps [Samek; also mentioned in this thread] is similar to statecharts.
I've used Rational Rhapsody for C++ and I think it's actually pretty good. But there be dragons there. UML alone is a tough sell to some engineering crowds, much less generating code from diagrams. Holy wars abounds.
While searching for related info to this post I discovered that W3 has a relevant specification . But I suppose it makes sense, IBM is a player here and they love XML there.