I recall a discussion about this in the developer's forum. There was somebody who wanted to do the same. Maybe you search the dev's forum. As far as I recall it's possible but basically you end up with Eclipse plugin development.
do you want to customize the 4.x or the 3.x GPD?
I don't mind doing some eclipse plugin development, but the less work the better. So Koen, I have not followed the development of 4.x, what is the difference between these two version in terms of customization?
The difference is that for 4.x a number of issues still have to be solved to make pluggability possible (see GPD-292 and http://www.jboss.org/index.html?module=bb&op=viewtopic&t=160930) For 3.x pluggability is already possible. The best place to start to see how it is done is to look at the ESB node.
Thanks, Koen. I am looking at the example in jbpm 3. The ESB node is a good example.
Any timeline for fixing problems of jbpm 4.x?