Seam consumes the jbpm API, and it would be great if you could include the methods we use as part of the stable API you are developing.

http://fisheye.jboss.org/browse/Seam/trunk/src/main/org/jboss/seam/bpm
and
http://fisheye.jboss.org/browse/Seam/trunk/src/main/org/jboss/seam/pageflow

is our integration code - ping me if you want to discuss this further offline.