I'm currently designing a new system to integrate one of our internal systems with an external 3rd party service, Drools Flow is perfect for what we're doing, as is JBoss ESB, I was kinda hoping the two were integrated but looking at this issue from a couple of years ago, it doesn't look like it is.
I'll probably just end up firing the Drools Flow from a custom ESB action (unless anyone has any better suggestions) but i thought I'd drop a note here to show that I would be interested in such a feature.