I hope I have some credits in this forum and I dare a cross post ;-)
I currently wrote an article about that in the German Java Magazin. It is not yet printed (in fact, if you want to review it send me a mail before the weekend, that would be nice :-)) but the example is already available online: http://www.camunda.com/knowledge/jbpm_meets_esb.html.
As soon as I get the article as PDF I will provide it there...
But the integration is overall really simple. Cool stuff :-)
You kind of live on a razors edge right? But yes... you have some credits in this forum