I wrote some blogs about jBPM and Spring integration. Changed quite a bit between 4.2 and 4.3 (and not for the better in my opinion).
See http://diversit.eu/2010/01/10/jbpm-4-3-with-spring/. I used Spring 3 and Autoconfiguration so it's just adding 1 line to your Spring config.
lately I noticed that you have replied to the comment I left under your article. Have you had the chance to talk to Alejandro about contributing or integrating your work in one of the next versions?