Tested your pasted BPMN2 with web Designer (http://www.jboss.org/jbpm/components/designer) and it worked without issues. I would try with latest release from sourceforge (http://sourceforge.net/projects/jbpm/files/designer/) and please report any issues you run into.
I have not used the new Eclipse editor much, so can't speak for it. Web Designer is very flexible in that it has independent release cycles from jBPM so we can turn around bug fixes very quickly to end users.